SHANGHAI, Mar. 15 (SMM) – Shanghai spot copper premiums were quoted between RMB 20-110/mt in the morning business. Traded prices for standard-quality copper were between RMB 56,750-56,900/mt, and RMB 56,800-57,050/mt for high-quality copper. SHFE copper prices marched higher after starting up, with the price gap between SHFE 1303 and 1304 copper contract expanding above RMB 100/mt. However, spot copper supply decreased sharply, forcing cargo-holders to hold prices firm during the last trading day for SHFE 1303 copper contract. Traders exhibited low buying interest due to high premiums, while downstream producers increased purchase volumes at lows but shifted to the sidelines following copper price surges.