Where does gravel come from?
  • Gravel starts out as huge boulders of rock under the ground.
  • Itís "quarried" which means itís blasted out into the open by dynamite or dug out by huge diggers and front end loaders then the boulders are carried in huge trucks to the crusher.
  • The crusher breaks the boulders into tiny pieces.
  • The chips of rock are sorted into sizes and types.
  • Then itís carried by truck and trailer units to building and road sites.
  Did You Know?
  • Gravel is a special type of rock thatís very hard.
  • A quarry is a huge pit that rock gets excavated or dug out from.
  • 750,000 truck and trailer loads of rock and aggregate is quarried in New Zealand every year. 84,000 tonnes.
  • The first excavators in New Zealand were the Maori. The used stone for axes and tools and they mined Greenstone or Pounamu from rivers in the Southern Alps for tools and jewellery.
Different types of rocks are used to different jobs. Gravel is used in road because it is very hard and it doesnít wear down easily. Find different types of rock and test them to see which is the toughest. You can try pumice, scoria, and gravel - theyíre some of the most common - youíll probably find them around your house.
Start the test by using your own weight - stand on the samples and see if you can crush them. Then try something heavier - get an adult to help you. You should find that gravel is by far the toughest.
Have a look around your playground. Maybe the footpaths have chips of stone in the concrete. Thatís gravel. Where else can you see gravel being used around your school? Maybe ask your teacher.

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