HistoryWorking classWorking class, united statesCopper Miners' Strike, Mich., 1913-1914Copper mines and miningEconomic conditionsEconomicsItalian Hall Disaster, Calumet, Mich., 1913Labor movementLabor movement, united statesMichigan, economic conditionsMinersPolitical activityRadicalismSocialismStrikes and lockoutsStrikes and lockouts, minersWorking class, political activity