SHANGHAI, Apr. 11 (SMM) –Premiums on spot copper were quoted between positive RMB 20-80/mt in Shanghai in the morning business Wednesday. Traded prices for standard-quality copper were between RMB 57,880-58,000/mt, and RMB 57,920-58,050/mt for high-quality copper. SHFE copper prices plunged by 2% but showed resilience, so the SHFE/LME copper price ratio failed to improve. Hedged copper, though, came into markets in large quantities, leading to a significant increase in spot copper supply. This made impossible for spot copper premiums to rise significantly with the slumping SHFE copper prices. Downstream producers and traders bought appropriately at low price levels, leaving market activity brisk in the morning trading. Overall supply still exceeded demand, however.