Antofagasta Minerals said its copper operations were unharmed by a strong earthquake in Chile on Tuesday.A 8.2 magnitude earthquake struck off the coast of northern Chile, causing five deaths and triggering a tsunami of two-metre waves. The quake was shallow at 20.1 km below the seabed and struck about 100km northwest of the mining port of Iquique near the Peruvian border, according to the US Geological Survey.However, copper miners appeared to be unscathed by the disaster.Even so, the price of the key industrial metal was changing hands at 6,696.75 recently, with three month copper futures advancing by about 1%.Shares in Antofagasta rose 1.91% to 855p at 09:14 on Wednesday.RD