SHANGHAI, Mar. 20 (SMM) – Spot copper premiums were RMB 80-250/mt in Shanghai on Wednesday. Traded prices for standard-quality copper were between RMB 55,350-55,600/mt, and RMB 55,450-55,700/mt for high-quality copper. Prices of the most active SHFE copper contracts rose after a low opening today. Speculators bought at low prices in the morning and hiked spot copper premiums after SHFE copper prices went up. High-quality copper prices were RMB 100/mt higher than standard-quality copper due to high demand. Later, spot premiums fell as downstream producers were cautious about buying. Few transactions were completed at mid-day.