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?  How did Britain used to look? How has it’s position on Earth changed over time?  Where did the coal come from?coal come from  Where did the limestone come from?limestone come from  Can you think of ways in which the rock salt formed?rock salt formed

Salt in Cheshire  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  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 Video on sea salt production

1. Mining  Also known as Dry Salt Mining – see videoDry Salt Mining

1. Salt Mining in the 19 th 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 21 st 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 ANIMATION  Solution Mining Video with Solution Mining Video formation of rock salt

Salt mining and the environment  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  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?  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?