Shanghai copper inched down on Tuesday under the weight of a firmer dollar and economic uncertainty ahead of US economic data this week, including key non-farm payroll numbers for April due on Friday. The most active Shanghai July copper contract closed 0.3 percent lower at 69,000 yuan by 0702 GMT, after a three-day weekend in China.
At the close of Shanghai Futures Exchange trade, the premium for May copper rose to 1,050 yuan versus the July contract , its widest backwardation in two years, suggesting strong demand for prompt material.