London and Shanghai copper prices dropped about 1 percent on Tuesday, weighed down by a recommendation from long-term commodity bull Goldman Sachs to close long positions in the metal and an escalating nuclear crisis in Japan. Shanghai's most active copper futures contract closed down 1.4 percent to 72,310 yuan a tonne, off a one-month high of 73,940 yuan hit in the previous session.
Front-month Shanghai copper was at a 140 yuan premium to the most-active third-month contract, down from a near 900 yuan contango in February.