CHILE — A magnitude 6.2 earthquake struck the northern coast of Chile on Saturday, the U.S. Geological Survey said.The quake was located 63 miles (101 km) northwest of the copper-exporting port of Iquique and had a depth of 7.1 miles (11 km), the USGS said.There was no immediate threat of a tsunami, according to the Pacific Tsunami Warning Center.Chile's massive mines are clustered in the mineral-rich north, including Collahuasi, a partnership between Glencore Xstrata and Anglo American.Earthquakes are frequent in the region and there was no word of any damages.