SHANGHAI, Mar. 15 (SMM) –Spot copper offers were quoted between premiums of positive RMB 20-100/mt in Shanghai in the morning business. Traded prices for standard-quality copper were between RMB 59,420-59,520/mt, and RMB 59,450-59,600/mt for high-quality copper. SHFE copper prices plunged, but the price gap between SHFE 1203 and 1204 copper contract held between RMB 300-400/mt, heightening some cargo-holders’ unwillingness in moving goods. Cargo-holders thus insisted on premiums at the last trading day for SHFE 1203 copper contract, hoping to move goods at high price levels Friday. Downstream producers bought as needed at the lows, so overall market activity improved.