Total copper stocks in the LME warehouse system have halved since mid-February to 132,400 tons, the lowest in almost a year.

The Tsumeb smelter is one of the few facilities in the world that can treat arsenic and lead-bearing copper concentrates.

ASM has concluded purchase orders from US-based Noveon Magnetics and Vacuumschmelze, owned by private equity firm ARA partners, for the supply of rare earth alloys, it said in a statement.