HOW IS SALT EXTRACTED?
C3 Lesson 4
Learning Outcomes



All … will list the different ways salt can be
extracted
Most …will describe the two main ways of
extracting salt from below the ground
Some … will evaluate the impact salt extraction can
have on the environment
Match the maps to the resource
Limestone
Coal
Salt
How did they get there?


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
How did Britain used to look? How has it’s position
on Earth changed over time?
Where did the coal come from?
Where did the limestone come from?
Can you think of ways in which the rock salt
formed?
Salt in Cheshire


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The Rock salt at Winsford
was formed 220 million
years ago when England
was covered by inland
seas.
Hot temperatures
evaporated the waters
extremely slowly leaving
large salt deposits under
the earth in and around
Cheshire.
Over time the rock salt
has been trapped under
layers and layers of
other sedimentary rocks.
Where do we get salt from?

We get salt from two main sources, what are they?

1. Sea water – by evaporation

2. Rock salt – by mining or solution mining

On an A4 spread, start a brainstorm of these three
methods – you need to know them in detail
Different salts, different uses


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sea salt – used in foods and chemical industry as it
is the cheapest to make. Sea salt has to be purified
before it can be eaten
Mining salt – used directly on roads when it is icey
Solution Mining Salt – used largely by chemical
industries
Sea salt

Video on sea salt production
1. Mining

Also known as Dry Salt Mining – see video
1. Salt Mining in the

th
19
Century
Traditionally, men were lowered down a tunnel and
used picks and shovels to excavate the salt. It was
carried up to the surface and sold.

Eventually
technology
advanced
and power
tools and
controlled
explosions
were used.
Mining in the

st
21
Century
Now mining is much more mechanised and involves
large, precision machinery.
2. Solution Mining
Instead of digging for the rock, water is used to
dissolve the salt and then pumped back up to the
surface
 SOLUTION MINING ANIMATION
 Solution Mining Video with
formation of rock salt

Salt mining and the environment


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Make a list of the impact that Dry Salt and Solution
Mining might have on the environment
You should think about plant life as well as animal
and human
You should think about the amount of energy, and
therefore fuel, is required in each method.
EXTENSION: can you think about the risk involved in
each method of salt mining
Rock Salt in Crowborough


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A deposit of rock salt has been found beneath
Crowborough.
In your groups decide on two things:
A – Should we mine for the rock salt?
B – Which method should we use?
Factors to consider:
• What infrastructure will be required?
(think about roads, traffic, trains,
housing, factories)
• Can Crowborough cope with a new
industry in the area?
• Which method of mining will be most
economical and environmentally
friendly?
What is your final decision?


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As a class vote for what you want to do about the
rock salt in Crowborough.
Who is most likely to benefit from your decision?
Who is it going to have greatest impact on?
Will anyone lose out?
What are the risks?
Are the outweighed by the benefits?