SHANGHAI, June 3 (SMM) – In the Shanghai physical market, copper was quoted Tuesday at a RMB 260-380/mt premium over the SHFE front-month copper contract. Traded prices were RMB 50,000-50,050/mt for standard-quality copper and RMB 50,060-50,160/mt for high-quality copper. Proportions of imported copper fell in the market after the northeastern Chinese port of Qingdao halted shipments of aluminum and copper due to an investigation by authorities. Some cargo holders of imported copper rushed to generate cash by cutting premiums slightly, while speculators expressed lower buying interest. Meanwhile, downstream producers largely stayed on the sidelines after physical copper prices rebounded above RMB 50,000/mt on Tuesday.