IT IS a union backed by the power of more than 10,000 members in the mining industry, and as the Queensland resources sector explodes, so, too, does the number joining.
The Construction, Forestry, Mining and Energy Union's (CFMEU) mining and energy division has landed in the headlines this year, in a storm of finger-pointing, accusations and court cases with BHP Billiton.
Its numbers equate to membership by at least a quarter of all mining industry workers.
Each member pays about $25 a week in membership fees, adding up to at least $13 million in revenue for this division of the greater CFMEU.
They may also pay extra to be a member of their mine's specific group within the greater union.
Those fees are funnelled to support workers during strike action, loved ones lost while either at work or commuting and for legal action.
Queensland district secretary Jim Valery said there was never pressure for workers to sign on.
He described union membership as akin to house insurance.
"You see a lot of bad scenarios where we have people who have made the choice not to become a member and you see horrific things happen to those people," Mr Valery said.
"But once a company burns someone, they come across to the union."