SHANGHAI, Oct. 21 (SMM) –Shanghai spot copper offers were quoted between premiums of positive RMB 500-700/mt today. Traded prices for standard-quality copper were between RMB 52,700-53,500/mt, and RMB 52,800-53,600/mt for high-quality copper. As SHFE copper prices fell after initially increasing, spot copper premiums held firm. Due to volatilities in copper prices, market transactions, resulting in sufficient market supply.