SHANGHAI, May 30 (SMM) – Spot copper premiums were quoted between positive RMB 150-230/mt in Shanghai in the morning business. Traded prices for standard-quality copper were between RMB 56,000-56,120/mt, and RMB 56,050-56,250/mt for high-quality copper. SHFE copper prices retreated sharply, and cargo-holders in spot markets sold aggressively, restricting spot copper premiums. Spot copper supply was diversified. Speculators without cash pressures chose to buy and favored high-quality copper, while downstream producers also made purchases at around RMB 56,000/mt. Overall transaction volumes remained light, though.