The strikes will occur during the night shift at six mines run by BHP Billiton and Mitsubishi and will continue with two day shift stoppages early next week.
Reuters reports that the mines have a production capacity of 58 million tonnes which is about a fifth of global trade in metallurgical coal used to make steel. The Construction, Forestry, Mining and Energy Union says the action is not a full-blown strike.
Mr Steve Smyth Queensland president of the CFMEU said "From our members' perspective, it's about causing some disruption otherwise you wouldn't take the action."
The unions representing the workers are calling for better pay for apprentices and a reduction in contractors as part of a claim to secure more of the record profits from the mining boom.
Workers had already engaged in several six hour stoppages last week. (sourced from ABC )