SHANGHAI, Nov. 18 (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 56,700-57,000/mt, and RMB 56,800-57,100/mt for high-quality copper. As SHFE copper prices moved higher after a low open, cargo-holders became more unwilling to move goods at the lows, helping spot copper premiums increase further. Supply of high-quality copper continued to contract. Purchases from downstream producers were modest, still purchasing on an as-needed basis, while some traders made limited intraday intermediary trade at the lows to avoid risks.