Demand fears continue to restrict the extent of upside moves, whilst supply disruptions at the mine level have more recently provided a floor to prices following the early-year sell-off.
The recurring phenomenon — a warming of the Pacific Ocean as part of a complex cycle linking atmosphere and ocean — has in the past affected mine output, triggering price spikes.
The Peruvian government has deployed troops near the Tia Maria copper project, to deal with the deaths of a protester and a policeman over the past week.
