Ausgeology. Queensland senior lessons

QCE Earth & Environmental Science · Unit 3 Topic 1: Use of non-renewable Earth resources

Should it be mined?

In October 1991, drilling about 38 km north-east of Cloncurry found copper and gold under 40 to 50 m of younger sediment (UQ Sustainable Minerals Institute; Evolution Mining). Your team works through the same kinds of data the explorers had, in a model, and decides, with today’s prices, laws and expectations, whether it should be mined.

How the lesson works

1 · The problem

Screen 1. Read the problem, take a role, and list what your team needs to find out.

2 · Investigate

Screens 2 to 9. Each screen is one part of a feasibility study: the ore body, its value, mining, processing, the environment, monitoring, the people with a say, and closure. Each ends with a team decision.

3 · Recommend

Screen 10. Your decisions come together as a report. Make your recommendation, then find out what really happened at Ernest Henry.

Your problem

A mining company’s board wants a feasibility study. Is the deposit worth mining? How should it be mined and processed? Can it be done without leaving damage behind, and who has a say? No decision is marked wrong: your recommendation is judged on the evidence behind it.

The deposit is Ernest Henry, a real mine. Your team decides first; screen 10 shows what happened.

Team roles

For a team of four or five. Each person leads the screens for their role, and the whole team agrees each decision.

  • Geologist

    Screens 2 and 3: where the ore is, how much there is and what it is worth.

  • Mining engineer

    Screen 4: how to get the ore out of the ground.

  • Metallurgist

    Screen 5: how to separate the metal from the rock.

  • Environmental scientist

    Screens 6, 7 and 9: impacts, monitoring and closure.

  • Community and approvals officer

    Screen 8: who has a say, and the permits the mine needs.

What we are learning

How mineral resources are found, valued, mined and processed, how mining affects the environment and how that is monitored, and how a feasibility study weighs all of these.

I can

  • 1interpret survey and drilling data to locate an ore body.
  • 2work out the value of a deposit from its tonnage, grade, recovery and metal prices.
  • 3explain how an ore body’s depth, shape and size decide how it is mined.
  • 4choose a separation method from a mineral’s physical and chemical properties.
  • 5describe how mining can affect the atmosphere, hydrosphere and biosphere.
  • 6set a trigger value from monitoring data and decide what to do when it is passed.
  • 7explain how permits, native title and the community shape whether a mine goes ahead.
  • 8describe what a rehabilitation and closure plan includes and why it is required.
  • 9make and justify a recommendation from a feasibility study.

QCE Earth & Environmental Science, Unit 3 Topic 1: Use of non-renewable Earth resources. The teacher notes at the end quote the topic’s Science understanding subject matter and show which screen covers each point.

My notebook

What does your team need to find out?

Tick what you think a feasibility study has to answer, then add anything else. Screens 2 to 9 take these one at a time.

Printable activity

Feasibility report

Four pages: a box for each screen, with space for the team’s decision and the evidence behind it, ending with the recommendation. Print one per team.

Feasibility report (PDF) Editable (Word)

2Investigate · geologist leads

Where is it?

Where is the ore, what shape is it, and how far does it go?

Nothing shows at the surface. The explorers had a magnetic survey, an electromagnetic survey and their first drill holes. Work out where the ore is before anyone spends money on a mine.

This screen · about 30 minutes

  1. Read how the deposit was found.
  2. Drill the section and log what each hole hits.
  3. Answer the check.
  4. Make the team decision.

How it was found

Ernest Henry lies under 40 to 50 m of younger cover, so there was nothing to see at the surface (UQ Sustainable Minerals Institute). “Magnetic methods were used to initially focus exploration”, and then “Transient electromagnetic (TEM) techniques were used to filter the magnetic target areas” (Webb and Rowston, 1995). The deposit was found in October 1991 by drilling into a ground TEM anomaly (UQ Sustainable Minerals Institute), and “The first drill hole into the deposit intersected economic copper and gold grades” (Webb and Rowston, 1995).

Then came a surprise. The TEM anomaly came from a layer near the top of the deposit where weathering had concentrated copper, partly as native copper. Drilling “demonstrated that the bulk of the primary mineralisation did not produce a TEM anomaly” (Webb and Rowston, 1995). The ore holds so much magnetite that it also shows as a 1.7 milligal gravity anomaly (UQ Sustainable Minerals Institute).

Drilling showed the ore body is shaped like a tilted cylinder. At its top it is about 400 m wide and 200 m high, and it runs down for at least 1.8 km (UQ Sustainable Minerals Institute), plunging at about 45° (Evolution Mining).

Most of the primary ore at Ernest Henry gave no TEM anomaly. What should the team do with the next drill holes?

Team decision

Do you know enough about the ore body to estimate how much there is?

2Investigate · geologist leads

Is it worth it?

Is there enough metal, at a high enough grade, to pay for a mine?

Rock with copper in it is only ore if the copper can be mined at a profit. Work out what the metal is worth, and find out what changes the answer.

This screen · about 30 minutes

  1. Read the real figures for Ernest Henry.
  2. Try the calculator with the resource and the reserve, then change the prices and your cost.
  3. Answer the check.
  4. Make the team decision.

Size, grade and price

A deposit's value depends on its tonnage, its grade, how much of the metal the plant can recover, and the price the metal sells for. Ernest Henry is still being mined. At 31 December 2024 its owner, Evolution Mining, reported a Mineral Resource of 110 million tonnes at 1.26% copper and 0.77 g/t gold, and a smaller Ore Reserve of 78 million tonnes at 0.76% copper and 0.46 g/t gold (Evolution Mining). The reserve is the part the company expects to mine: Ore Reserves “will all be mined”, as Geoscience Australia puts it.

In 2024–25 the plant recovered about 96% of the copper and 79% of the gold (Evolution Mining). Evolution's guidance for 2025–26 assumed a copper price of $14,500 a tonne and a gold price of $4,400 an ounce (Evolution Mining). Prices move every day, so a feasibility study tests what happens if they fall.

Costs matter too, and not only the mine's. Ernest Henry's concentrate is treated at Glencore's smelter in Mount Isa (Evolution Mining). In 2025 Glencore said it might have to close the smelter, and in October the federal and Queensland governments agreed to share an A$600 million rescue over three years, as smelters “grapple with rock-bottom fees amid overcapacity in China” (Mining.com, 2025).

Up to 2011, Ernest Henry produced 1.56 million tonnes of copper from ore averaging 1.05% copper (UQ Sustainable Minerals Institute). If every bit of the copper was recovered, roughly how much ore was mined?

Team decision

Is the deposit worth a full feasibility study?

2Investigate · mining engineer leads

How to mine it.

How do the ore body's depth, shape and size decide how it is mined?

The top of the ore is only 40 to 50 m down, but the ore body plunges at about 45° for at least 1.8 km. Choose how to get it out.

This screen · about 25 minutes

  1. Compare open-cut and underground mining.
  2. Use the pit model to find where a pit stops paying.
  3. Answer the check.
  4. Make the team decision.

  • Open cut

    A pit is dug down from the surface in steps called benches. All the waste rock above and beside the ore has to be dug out too. It suits large ore bodies near the surface, even low-grade ones.

  • Underground

    Shafts or sloping tunnels called declines reach the ore, which is broken in spaces called stopes and hoisted or trucked out. Far less waste rock is moved, so it suits deep ore and rich ore.

What Ernest Henry did

Ernest Henry was mined from an open pit from 1997 to 2011, to a depth of 650 m (UQ Sustainable Minerals Institute). The final pit was never finished: “south wall instability prevented completion of the final open pit shell” (McGrath and others, 2014). Since 2011 the ore below the old pit has been mined underground by sublevel caving (UQ Sustainable Minerals Institute; Evolution Mining), and since 2014 it has been hoisted up a shaft a kilometre deep (Evolution Mining).

Ernest Henry's ore continues more than a kilometre below the surface. Why was the deeper ore mined underground instead of by making the pit bigger?

Team decision

How should the deposit be mined?

2Investigate · metallurgist leads

How to process it.

How do a mineral's physical and chemical properties decide how it is separated from the rock?

Ore at about 1% copper is mostly waste rock. Before it can be sold, the copper minerals have to be separated out. Each method uses a property that the mineral has and the waste rock does not.

This screen · about 30 minutes

  1. Read how the ore is processed, then put Ernest Henry's steps in order.
  2. Sort the minerals by the method that separates them.
  3. Compare mineral sands and alluvial gold.
  4. Answer the check and make the team decision.

From ore to metal

First the ore is crushed, then “ground finely before the copper-bearing sulfide minerals are concentrated by a flotation process” (Geoscience Australia). The main copper mineral is chalcopyrite, a copper iron sulfide (Geoscience Australia). In froth flotation, the ground ore is stirred with water and chemicals that “bind to the surface of the mineral particles and make them hydrophobic”. Those particles stick to air bubbles and are carried up into a froth, which is skimmed off (Britannica). The concentrate “typically contains between 25 and 30% copper” (Geoscience Australia).

At Ernest Henry, copper and gold “are recovered from the ore using traditional grinding and flotation methods in the concentrator”, which makes one copper, gold and silver concentrate (Evolution Mining). The plant also has a circuit for magnetite, which is now in care and maintenance (Evolution Mining). “Magnetite ore is further processed through magnetic separation” (Geoscience Australia). The concentrate goes to Glencore's smelter at Mount Isa, and the metal is refined at Glencore's refinery in Townsville (Evolution Mining). Smelting melts the concentrate to make copper metal, which is “finally electrolytically refined to pure cathode copper” (Geoscience Australia).

Put Ernest Henry's steps in order

Which method separates it?

  • Minjerribah (North Stradbroke Island)

    Mineral sands

    Sand mining on Minjerribah began in 1949, and the last mine, Enterprise, was due to stop operating in December 2019 (Queensland Government, 2019; NASA Earth Observatory, 2020). Enterprise and Yarraman mainly extracted “mineral sands such as zircon, rutile, and ilmenite” (NASA Earth Observatory, 2020). These heavy minerals are separated from the lighter quartz sand by gravity, then from each other by magnetism and by whether they conduct electricity (Mitchell, 1992).

  • Gympie and the Palmer River

    Alluvial gold

    Both goldfields began with alluvial gold. At Gympie “The alluvial gold deposits were mined within a year” (Queensland State Archives, 2021), and the Palmer River “was initially a very rich alluvial field” (State Library of Queensland, 2013). Gold is so dense that it sinks faster than sand in moving water (Britannica). In a sluice, gravel is washed along a channel, and riffles across its floor slow the water “so that gold may settle and be trapped” (Britannica).

A plant treats 100 t of ore at 1% copper. It recovers 96% of the copper, in concentrate at 25% copper. About how much concentrate does it make?

Team decision

Which processing plan goes in your report?

2Investigate · environmental scientist leads

Land, water and air.

How could this mine affect the atmosphere, hydrosphere and biosphere, and which risk matters most?

Two old Queensland mines show what can go wrong. Use them to judge the risks at your site.

This screen · about 30 minutes

  1. Read about acid and metalliferous drainage and the two case studies.
  2. Sort the impacts into spheres.
  3. Answer the check.
  4. Make the team decision.

When rock meets air and water

Mining breaks up rock that has been sealed underground and leaves it in waste rock dumps and tailings. Where that rock holds sulfide minerals such as pyrite, “the sulphides react with water and oxygen to form sulfuric acid” (Fitzroy Partnership for River Health). The acid dissolves metals from the rock and carries them into creeks and groundwater: acid and metalliferous drainage. Pyrite is one of the minerals in the inner part of the Ernest Henry ore body (UQ Sustainable Minerals Institute).

Before a large mine is approved, the Queensland Government can require an environmental impact statement. An EIS is “a tool the government uses to assess” the environment as it is, the project's potential impacts, and ways to avoid, minimise, mitigate or offset them, and the public can have their say on it (Queensland Government, 2022).

  • Central Queensland

    Mount Morgan

    Mount Morgan began as a gold mining town in 1882, and mining went on until November 1990. The Queensland Government took over the site's problems in January 1993, including “poor quality water associated with acid mine drainage on-site and downstream in the Dee River” (Queensland Government). In 2007 researchers reported that the river was “highly polluted up to 20km”, and one said “We could not find a single fish and single algae at the site close to the mine site” (CQUniversity, 2007).

  • 60 km east of Mount Isa

    Mary Kathleen

    Uranium was mined from an open pit here in two campaigns, the second ending in 1982. The operator decommissioned the site between 1982 and 1985 at a cost of $19 million, but it still has “poor-quality water associated with acid and metalliferous drainage from the pit and tailing storage facilities” (Queensland Government).

Which sphere does it affect first?

Pyrite is one of the minerals in the Ernest Henry ore body. Why does that matter for the mine's waste rock and tailings?

Team decision

Which impact is the biggest risk at this site?

2Investigate · environmental scientist leads

How will you know?

How do you monitor a mine's environment, and what do you do when a reading is too high?

A mine's environmental authority sets what it must monitor and the trigger levels that call for action (Bourke and Hiles, 2019). Set trigger values for the creek below your mine, test them against a release, and see how far a settling pond can clear muddy water.

This screen · about 40 minutes

  1. Read what is monitored and how trigger values are set.
  2. Set a trigger value from the upstream data, then test the release readings against it.
  3. Try the settling pond model.
  4. Answer the two checks and make the team decision.

What is monitored

The Queensland syllabus lists common measures: air quality (such as ozone, sulfur dioxide, carbon monoxide, visibility and fine particles called PM10), water quality (such as pH, dissolved oxygen, turbidity and biochemical oxygen demand), soil quality (pH, erosion and changes in soil structure), the distribution and abundance of living things (line transects and the Lincoln index), and noise (sound level meters, sleep patterns) (QCAA, 2024).

Trigger values

A trigger value is a level that, once passed, calls for action: at the mine described below, a comparison with upstream and, if downstream is worse, an investigation. The national water quality guidelines suggest setting it from a reference site upstream that mining does not affect, at “Typically, the 80th percentile” of its readings, or the 20th percentile for something that causes harm when it falls, such as dissolved oxygen. Queensland asks for “a minimum of 18 samples collected at 1 to 2 reference sites over at least 12 months”, and the downstream readings are compared using their annual median. The guidelines call the trigger a guideline value (ANZG).

At one Queensland coal mine, if a downstream reading during a release passes its trigger, it is compared with the upstream reading. If it is no higher than upstream, nothing more is needed. If it is higher, the company must “complete an investigation into the potential for environmental harm” and report within 90 days (Bourke and Hiles, 2019).

Settling ponds

Rain on bare ground at a mine turns runoff muddy. In a settling pond the water slows down and the particles sink. Placer miners in Canada use them “due to their efficiency, simplicity and low cost”, but “it is much more difficult to settle suspended fine silts and clays”, and “Very small improvements in effluent quality require very large increases in settling pond sizes” (Klondike Placer Miners' Association, 2004).

During a release, the downstream electrical conductivity passes its trigger value. The upstream reading on the same day is even higher. What happens next, under the condition described above?

Surveyors catch and mark 40 fish in the creek below the mine, then release them. A week later they catch 50 fish, and 10 of them are marked. What is the Lincoln index estimate of the population?

Team decision

When the downstream median passes a trigger value during a release, what will your plan do?

2Investigate · community and approvals officer leads

Who else has a say?

Who has rights in the land, who will the mine affect, and what permits does it need?

A mine needs more than ore. It needs the right permits, agreement with the people whose country it is on, and the trust of the town nearby.

This screen · about 25 minutes

  1. Read about native title, the permits and the community.
  2. Match each issue to the permit or process that deals with it.
  3. Answer the check.
  4. Make the team decision.

Country and native title

Ernest Henry is on the traditional lands of the Mitakoodi and Mayi peoples (Evolution Mining). Native title is “the recognition in Australian law that some Indigenous people continue to hold rights to their land and waters”. The High Court recognised it in the Mabo decision in 1992, and the Native Title Act followed in 1993 (National Native Title Tribunal). When Ernest Henry was found in 1991, native title had not yet been recognised and the Act had not been passed.

Today, granting a mining lease is a ‘future act’ under native title law. The right to negotiate process “allows you to reach agreement with the native title party or parties that overlap your resource authority”. If there is no agreement 6 months after the notification day, either side can ask the National Native Title Tribunal to decide whether the mining lease may be granted, granted with conditions, or not granted (Business Queensland).

Permits

In Queensland an exploration permit lets a company search a large area, a mineral development licence holds a deposit that cannot yet be mined at a profit, and a mining lease is needed for a full-scale mine. Each of these also needs an environmental authority (Queensland Law Handbook). Anyone can object to a mining lease application; the Land Court hears the objections and makes a recommendation to the Minister. Landholders affected by a mine “generally also have a right to compensation for the loss of use of their land” (Queensland Law Handbook).

The town

In 2024–25 Ernest Henry employed about 640 people, plus about 360 contractors, and its concentrate was trucked about 150 km to Mount Isa (Evolution Mining). Jobs and business come with dust, noise and traffic, which is why noise and air quality are on the monitoring list.

Which permit or process deals with it?

Ernest Henry was found in 1991. Which part of today's approval process did not exist then?

Team decision

What will your company commit to before it applies for a mining lease?

2Investigate · environmental scientist leads

How it ends.

What should happen to the site when mining stops, and who pays for it?

Every mine closes. A feasibility study has to show how the land will be left, and that the money for it will be there.

This screen · about 20 minutes

  1. Read what Queensland requires.
  2. Compare three closures.
  3. Answer the check.
  4. Make the team decision.

What Queensland requires

All mining projects that apply for a site-specific environmental authority for a mining lease must provide a progressive rehabilitation and closure plan (PRC plan), and the requirement “commenced on 1 November 2019” (Queensland Government). Its schedule sets “milestones with completion dates for achieving progressive rehabilitation of the mine site”, so land is rehabilitated while mining goes on, not only at the end. Companies also provide financial assurance, by paying into a financial provisioning fund or giving a surety, which a scheme manager looks after on behalf of the State (Queensland Government).

  • Mary Kathleen

    Closed and decommissioned

    The operator decommissioned the mine between 1982 and 1985 at a cost of $19 million (Queensland Government). Acid and metalliferous drainage from the pit and the tailings storage facilities still has to be managed, and the site is now one of the state's remediation projects (Queensland Government).

  • Mount Morgan

    Left to the state

    The Queensland Government took over the site's problems in January 1993. Mining left 134 million tonnes of waste rock and tailings, and the water is managed by “evaporation, seepage interception and pump back activities” and a water treatment plant (Queensland Government).

  • Minjerribah

    Handed back

    Sand mining ended in 2019 (Queensland Government, 2019; NASA Earth Observatory, 2020). Sibelco committed to rehabilitate and surrender more than 12,248 hectares, working with the Quandamooka people, and the government’s page, updated in July 2023, says 2,860 hectares of mining lease had already been surrendered (Queensland Government, 2023).

Mary Kathleen was decommissioned by 1985 at a cost of $19 million, but its drainage still has to be managed. What does that suggest a closure plan should include?

Team decision

What will your closure plan promise?

3Recommend · the whole team

Your recommendation.

Should it be mined?

Your team's decisions are gathered below. Read them through, make your recommendation, then find out what really happened at Ernest Henry.

This screen · about 40 minutes

  1. Show your report and check every section has a decision and a reason.
  2. Make your recommendation.
  3. Open what happened at Ernest Henry and compare.
  4. Answer the nine questions.

Your feasibility study so far

Your decisions and reasons save in this browser as you go. The report gathers them in order. Copy it into a document to add your drill log, calculations and graphs.

Team recommendation

Should it be mined?
What happened at Ernest Henry (open this once your team has decided)

The deposit was found in October 1991 (UQ Sustainable Minerals Institute). Open-pit mining began in 1997 (UQ Sustainable Minerals Institute), and commercial production in 1998 (Evolution Mining). The final pit was never finished because the south wall was unstable (McGrath and others, 2014). In 2009 Xstrata, the owner at the time, announced a $589 million move underground, and trucking ore from underground began in December 2011 (Evolution Mining). Since 2014 the ore has been hoisted up a shaft a kilometre deep (Evolution Mining).

Evolution Mining bought the whole mine in 2022. A study in 2023 doubled the Ore Reserves and extended the mine's life to 2040 (Evolution Mining). In 2024–25 the mine produced about 47,800 tonnes of copper and 70,600 ounces of gold (Evolution Mining).

Some things would be different if it were found today. The Native Title Act was passed in 1993, two years after the discovery (National Native Title Tribunal), and Queensland's PRC plans began in 2019 (Queensland Government).

Show what you know

Nine questions, one for each of the I can statements on screen 1. You get one try at each, so think before you tap.

A magnetic survey finds a strong anomaly. The first hole drilled into it hits rock full of magnetite but almost no copper. What does this show?

The copper price falls by a third and nothing else changes. What happens to the deposit?

A narrow, rich gold vein lies 600 m below the surface. Which method suits it best?

Zircon and rutile are both heavy and non-magnetic. Which method can separate them?

Dust from a mine's haul road settles on the plants beside it. Which spheres are affected?

Upstream turbidity readings over two years have an 80th percentile of 20 NTU. During a release the downstream median is 35 NTU, and upstream on the same days it was 8 NTU. What should happen?

A mining company and the native title party have not agreed 6 months after the notification day. What can happen next?

Why does a Queensland PRC plan set dated milestones while the mine is still running?

Which recommendation is best supported?

Printable activity

Feasibility report

Four pages: a box for each screen, with space for the team’s decision and the evidence behind it, ending with the recommendation. Print one per team.

Feasibility report (PDF) Editable (Word)
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.

The lesson is built around the feasibility study, so it covers the topic from exploration to closure for one metallic deposit, with mineral sands and alluvial gold for comparison. Where it covers the subject matter:

  • Metallic and non-metallic resources: screen 5 (copper, gold and magnetite at Ernest Henry; mineral sands on Minjerribah). The lesson does not set out metallic, non-metallic and energy resources side by side, or cover energy resources.
  • Formation: not covered, apart from a mention of alluvial gold and mineral sands on screen 5.
  • Exploration: screen 2 (magnetic and electromagnetic surveys, the gravity anomaly, drilling, and the drill log, which gives the density of the ore against the rock around it), x1.
  • The feasibility study: the whole lesson. Size and value, with economic factors: screen 3 (the calculator and the future of the Mount Isa smelter), x2. Extraction methods: screen 4. Refining: screen 5. Environmental impacts: screen 6. Rehabilitation plan: screen 9. Infrastructure and site access: screens 3, 5 and 8 (the haul to Mount Isa, the smelter and refinery). Social impacts: screen 8 (native title, jobs, the town).
  • Extraction methods: screen 4 (open cut and underground mining, stopes, sublevel caving, the pit model), x3.
  • Choosing separation and processing methods from physical and chemical properties: screen 5 (froth flotation for chalcopyrite, magnetic separation for magnetite and ilmenite, gravity separation for coarse gold and heavy mineral sand, electrostatic separation for rutile and zircon, sluicing, smelting and refining), x4.
  • How extraction affects the atmosphere, hydrosphere and biosphere: screen 6 (acid and metalliferous drainage, Mount Morgan, Mary Kathleen, the sort), x5.
  • Monitoring, interpreting monitoring data and the effectiveness of strategies: screen 7 (the syllabus’s list of measures, trigger values from reference-site data, a release tested against them, the Lincoln index), x6.
  • Turbidity management with settling ponds: screen 7 (the pond model).

The lesson does not cover literature and historic records, satellite, aerial and hyperspectral imaging, soil, rock and auger sampling, room and pillar mining, dredging, drilling and fracking for oil and gas, or formation of the resources. The topic’s other lessons on the Queensland page cover formation, and coal, oil and gas.

Of the Science as a human endeavour points, screen 8 covers licensing and permissions; screen 7 covers using quantitative monitoring data to judge the risk to the environment, and nominating trigger values and acting on them; screen 6 covers the purpose of an EIS; and screen 2 shows how geophysical datasets narrowed the search. The lesson does not cover carbon pricing, the economic risk of coal seam gas exploration, community concern over coal seam gas, or modelling resource distribution with software and checking it with seismic surveys. Of the Science inquiry points, the drill section gives practice in investigating exploration data to predict where a resource is, and the pond model and the separation sort lead into two practical investigations: modelling settling ponds, and modelling separation.

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 calculations on screens 3, 5 and 7 and the monitoring data give practice for the data test, and a settling pond or separation model can be developed into a student experiment. The research investigation is set on Unit 4 subject matter.

How the lesson is taught

Problem-based learning. Students meet the problem first and list what they need to find out, then investigate one part of it on each screen. Each screen ends with a team decision and a reason, saved in the browser, and screen 10 gathers them into a report. No decision is marked wrong; the check questions on each screen test the science. A team that recommends against mining can be as well supported as one that recommends for it.

Teams of four or five work best, with the roles on screen 1; in a team of four, one person takes two roles. The screens take about 20 to 40 minutes each, so plan four or five lessons, or share screens 2 to 9 between teams and have each report back. The printable feasibility report follows the screens, for teams working on paper.

Ernest Henry is used as a historical problem: students work through the kinds of data from the 1991 discovery, in a model, but decide with today’s prices and rules, then compare their decisions with what happened. The account of what happened is folded on screen 10 so that teams decide first.

Handle with care

  • Ernest Henry is on the traditional lands of the Mitakoodi and Mayi peoples, as Evolution Mining names them. To go further, invite local Traditional Owners, following your school’s protocols.
  • Some students may have family working in mining, or strong views against it. The decisions are about evidence, not about whether mining is good or bad.

About the data and the models

  • Drill section (screen 2): the shape follows the UQ atlas and Evolution Mining (the top under 40 to 50 m of cover, plunging at about 45° to the south-south-east). The hole grades, the densities and the magnetic profile are made up.
  • Value calculator (screen 3): the resource and reserve (at 31 December 2024), recoveries (2024–25) and prices (the ones Evolution’s cost guidance for 2025–26 is based on) are Evolution Mining’s. The fact sheet gives the prices in dollars without naming the currency. The cost per tonne is the students’ own estimate, and the calculator leaves out smelter charges, transport, royalties, tax and the cost of building the mine.
  • Pit model (screen 4): shared with the Ore deposits lessons. The ore is a square block and the pit walls slope at 45°.
  • Monitoring (screen 7): the readings are made up. The trigger value is the 80th percentile of 24 monthly reference readings (the 20th for dissolved oxygen), worked out by linear interpolation, as a spreadsheet’s PERCENTILE.INC does. The response to a passed trigger follows the condition in the New Acland monitoring program; conditions differ from mine to mine. Comparing the median of the six release readings is a simplification: the guidelines compare an annual median, and the New Acland condition compares results.
  • Settling pond (screen 7): turbidity leaving = floor + (inflow − floor) × e−kt, with an inflow of 2,000 NTU, floors of 100 NTU for sand and coarse silt and 400 NTU for clay-rich water, and k of 0.6 and 0.12 per hour. The 100 NTU floor is the lowest turbidity the Klondike Placer Miners’ Association guide reports for settling ponds; the other values are chosen to show the shape of the curves.

Where sources disagree

  • Distance from Cloncurry: Evolution Mining gives 38 km north-east, and Webb and Rowston (1995) about 30 km north-north-east. The lesson uses Evolution’s figure.
  • When mining began: the UQ atlas has open-pit mining from 1997, and Evolution Mining has commercial production from 1998. The lesson gives both.
  • Gold in the resource: 110 million tonnes at 0.77 g/t works out at about 2.7 million ounces, and Evolution reports 2.8 million; the fact sheet does not show why. The calculator shows the worked figure.
  • The ore body’s plunge: the UQ atlas gives about 40° to the south; Evolution Mining gives about 45° to the south-south-east, as do Carr and others (2009). The lesson uses 45°.
  • Pit depth: the UQ atlas gives 650 m for the open cut, while Carr and others (2009) describe a final pit design 530 m deep, and the final pit shell was never completed (McGrath and others, 2014). The lesson gives the UQ figure.

Answers at a glance

  • q-find: follow the ore with the magnetic and gravity data and the drill results. q-worth: about 150 million tonnes. q-mine: the waste rock grows much faster than the ore. q-process: about 4 t.
  • q-impacts: pyrite can form sulfuric acid. q-trigger: nothing more is needed. q-lincoln: 200. q-people: native title negotiation. q-close: long-term water management.
  • Show what you know: x1 surveys show changes in rock properties, drilling shows ore; x2 a third less, lowest grades may not pay; x3 underground; x4 electrostatic separation; x5 atmosphere and biosphere; x6 investigate; x7 the National Native Title Tribunal can decide; x8 progressive rehabilitation; x9 the recommendation that uses evidence from several parts of the study.
  • Card sorts: flotation for chalcopyrite; magnetic for magnetite and ilmenite; gravity for coarse gold and heavy mineral sand; electrostatic for rutile and zircon. Impacts: dust and sulfur dioxide, atmosphere; drainage and pumped groundwater, hydrosphere; clearing and the river below Mount Morgan, biosphere. Permits: the right to mine, mining lease; water releases, environmental authority; agreement with the Mitakoodi and Mayi peoples, right to negotiate; a landholder’s objection, Land Court.

Saved progress

Answers, choices, readings and notes are saved only in this browser on this device. Nothing is sent anywhere.

References

Word list