Australian coal mines owned by BHP Billiton and Mitsubishi Corp <8058.T> will be hit by a second work stoppage on April 12, with union workers planning to halt work for two days, a union official said on Thursday.

We're looking at next Thursday's night shift to start the stoppage through to Saturday day shift at all seven mines, Construction, Forestry, Mining and Energy Union (CFMEU) District President Stephen Smyth told Reuters.

There also may be other industrial action taken, Smyth said. About 3,500 employees led by the CFMEU completed a seven-day strike on Tuesday after talks over working conditions and union entitlements broke down.

The seven mines, operated under the BHP Billiton-Mitsubishi Alliance joint venture, have a combined output capacity of more than 58 million tonnes a year, representing about a fifth of annual global trade in metallurgical coal.

(Reporting by James Regan; Editing by Ed Davies)