Altona Mining and Xstrata are expected to ask an independent expert to value Altona’s Roseby copper tenements after four weeks negotiating its worth.

Altona shareholders expect an update on the Roseby sales process as early as today, after hitting the first deadline in talks with Xstrata. Xstrata’s Mt Isa Mines intends to exercise a seven-year-old option and buy a 51 per cent stake in Roseby.