Complex sentence: Mexican copper miners in the northern state of Sonora taking action in the 1906 Cananea strike, where, among other grievances, they were paid less than U.S. nationals working in the mines.
Split into simpler sentences: Mexican copper miners in the northern state of Sonora took action in the 1906 Cananea strike. Among other grievances, they were paid less than U.S. nationals working in the mines.