UPDATE 1-Chile mines unharmed by quake; some ports shut

(Adds details on other mines, roads, context) SANTIAGO, April 2 (Reuters) - Copper operations in the world's top producer were broadly unharmed after a major earthquake in mineral-rich northern Chile on Tuesday night spooked miners and prompted some preventive evacuation of workers. Still, several metal-exporting ports in the Andean country remained closed on Wednesday morning following a tsunami evacuation, suggesting trade flows might be temporarily interrupted. The copper price