BMA has been stuck in a stalemate with the Construction, Forestry, Mining and Energy Union and other unions for more than 15 months.
The main sticking points for the workers are housing, safety representatives and equal pay for equal work.
The strike action from seven of BMA’s mines started on Tuesday night and was set to run for 48 hours.
CFMEU district president Stephen Smyth told the ABC that BMA had defaulted on a rostering agreement which was already in place, spurring the strike action.
“At this stage, what BHP have done today is nothing more than a slap in the face for our members, their employees,” Smyth was quoted as saying.
“We see this as a threshold matter, particularly in relation to the issue of rosters which we thought we put to bed over six months ago.”
Smyth warned the two-day strike could now be extended.
The strike action marks yet another round of industrial action in what has turned into a long-running bitter dispute between the parties, with all attempts at negotiations failing.
Last month, more than 3000 workers at BMA coal mines staged a week-long strike after the unions claimed the mining giant was not injecting enough of its profits into its workers.
