V. Decide whether the following statements are true or false.
1)
Coal is an inflammable black or brown sedimentary rock.
2)
The pressure and heat from the top layers helped the plant remains turn into coal.
3)
Bituminous coal formed about 100 to 300 million years ago is the least widespread rank of
coal in the US.
4)
Bituminous coal has a higher heating value than subbitumi- nous coal.
5)
Lignite is a relatively young coal deposit.
6)
Surface mining is cheaper than underground mining.
7)
Rocks and dirt, sulfur and unwanted materials are removed from coal at a preparation plant.
8)
Coal is burnt by power plants to make steam.
9)
Coke is used for smelting iron ore into iron.
10) The strength and flexibility are given to steel by the use of coke.
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