It remains uncertain when work on the shafts providing ventilation to support the production ramp-up for Panels 1 and 2 at the Oyu Tolgoi underground project, in Mongolia, will be able to resume. Rio Tinto-owned Turquoise Hill said on Friday that sinking works at shafts 3 and 4, which have been on care and maintenance since April, was dependent on specialist personnel returning to site.
