that is known as : Volunteer Reinforcement
Since the house has a very limited man power to do some tasks that is very important for the Government, they often ask for Public's help to do it for them ( usually those who support the current Government officials)
Eso no estaría en un libro?
Iron ore. It is used to create steel, and of the top three iron ore companies in the world two are in Australia.
Answer: Idiomatic expression
An idiomatic expression is an Informal English word whose meaning is different.
Like in the example "we are out of milk." Literally, it means that there is no more milk. If it is taken as an idiomatic expression, it would be taken differently, depending on the culture or the situation.