Metal Mining Methods
Why the richest metal ores are running out, and the greener ways chemists get metals from low-grade ore instead: phytomining with plants and bioleaching with bacteria, weighed against traditional mining.
Get the method right under pressure
Free interactive practice on the steps that lose marks under exam pressure.
Start revising freeWhat you'll cover
Running low on metal ores
We rely on the finite resources of the planet for energy, transport, food, clothing and housing. Metal ores are one of those finite resources, and the richest ores are running out. Sustainable development means meeting the needs of today without spoiling things for future generations, so chemists have found greener ways to win metals from low-grade ore that was once seen as waste. In phytomining, plants take up metal compounds as they grow and are then burned to an ash rich in the metal. In bioleaching, bacteria break down ore to give a solution the metal can be recovered from. This module covers both methods and how they compare with digging huge mines.
Resource words
Learn these before you compare any method, and notice which two describe living things doing the work.
Plants against bacteria
Phytomining and bioleaching both get metal from low-grade ore, but different living things do the work. This module defines how each one runs.
How to weigh an extraction method
To judge a way of getting metal, do not just describe it. Ask what it gives you and what it costs. Both biological methods let a business reach metal locked in poor ore that mining would ignore, and they scar the landscape far less. The price is time, because growing plants or bacteria is slow. So a strong answer names one clear gain and sets it against one clear drawback for the situation described, rather than listing points on only one side.
Match the method to how it works
- phytomining
- bioleaching
- traditional mining
- sustainable development
- plants soak up the metal and are burned to ash
- bacteria turn the ore into a metal-rich solution
- large amounts of rock are dug straight from the ground
- using resources so future generations are not left short
Which method is this?
A mining firm grows a crop on land too poor to dig. The plants take up copper as they grow, and the harvest is burned so the copper can be taken from the ash. Which method is being used?
- Phytomining.
- Bioleaching.
- Blast furnace reduction.
- Electrolysis of molten ore.
Why use these methods
Select the TWO real reasons a business turns to phytomining or bioleaching.
- They can win metal from low-grade ore that mining would waste
- They damage the landscape far less than a large mine
- They are always faster than digging a mine
- They need no energy or processing at all
Copper in the ash
A crop grown to gather copper is harvested and burned, giving 500 kg of ash. The ash is 8 per cent copper by mass. Work out the mass of copper in the ash, in kilograms.
Order the phytomining steps
Put the stages of phytomining in order, earliest first.
- Plants are grown on low-grade ore or soil
- The plants absorb metal compounds as they grow
- The plants are harvested and burned
- The metal is taken from the metal-rich ash
Complete the facts
A resource such as a metal ore that will one day run out is a _____ resource. Meeting the needs of today without harming future generations is _____ development. Growing plants that soak up a metal and then burning them is _____. Using bacteria to turn ore into a metal-rich solution is _____.
Match the idea to its point
- an advantage of the biological methods
- a drawback of the biological methods
- why the methods are needed now
- what traditional mining does
- far less harm to the landscape
- they work much more slowly
- the richest ores are running out
- digs and moves huge amounts of rock
Spot the true extraction facts
Tap the TWO statements that are true about these methods.
- Phytomining uses plants that are burned to ash
- Bioleaching uses bacteria to release the metal
- Both methods are faster than traditional mining
- Metal ores are an unlimited resource
Judge the method
Read each case and choose the best response, with a reason.
- A company owns land with only low-grade copper ore and wants to avoid a huge, damaging mine. Which method suits it best?
- A manager wants the copper as quickly as possible, whatever the cost. What is the honest drawback of the biological methods here?
- A student says these methods do not matter because ore will last forever. How should you respond?
Explain the greener extraction methods
Explain why chemists use phytomining and bioleaching, and compare them with traditional mining.
- Explain why metal ores are a finite resource and what sustainable development means
- Describe how phytomining gets metal from low-grade ore
- Describe how bioleaching gets metal from low-grade ore
- Give one advantage of these methods over traditional mining
- Give one disadvantage and finish with a judgement for a low-grade ore site