It's an unwelcome development for the exchange after it had to suspend the nickel contract in March, writes Andy Home.

The Federation of Copper Workers started the strike early Wednesday morning.

The premium for spot zinc over futures spiked on Thursday to the widest since 1997.

"The commodity world’s flagship is under fire,” one analyst said.

The blockade signaled a new conflict just two weeks after the mining firm resumed operations.

The new conflict comes just two weeks after the mining firm resumed operations following another protest that forced Las Bambas to shut down for more than 50 days.

Ruling ends string of litigation for one of copper-nickel project's key permits.