While the whole London Metal Exchange base metals complex ended the month on solidly higher prices than at the start of April on a recent bullish streak, a dollar index at its highest in a week pushed down copper and aluminium prices at the close on Friday April 30.
The dollar index reached 91.29 on Friday during afternoon trading, its highest since April 23 after bottoming at 90.42 on Thursday, reversing the gains made by some of the base metals this week.
Copper's three-month price was among those, turning lower on Friday to close at $9,825 per tonne, down $60 from Thursday.
The red metal did reach $10,008 per tonne on Thursday, closing in on the all-time high of $10,190 per tonne from February 2011.
"The next week or so could be critical for...