SHANGHAI, Sept. 8 (SMM) –Shanghai spot copper offers were quoted between discounts of negative RMB 50/mt and premiums of positive RMB 20/mt today. Trade prices for standard-quality copper were between RMB 67,850-67,900/mt in the morning business, and RMB 67,950-68,000/mt for high-quality copper. As SHFE copper prices failed to rebound, spot copper prices hovered around RMB 68,000/mt, keeping both speculators and downstream producers on the sidelines. Copper supply remained sufficient, and weak transactions resulted in limited room for premiums.