The merger has been planned on the basis of the recently concluded 46% upgrade in the JORC classified mineral resource to 4.4million tonnes at 129grams per tonnes silver for 18.3 million ounces.
MacPhersons Resources managing director Morrie Goodz said, "The pit optimisation studies all support a single superpit model, which is what we predicted when the new mineralisation zone at Lens 3 was intersected,"
"The drilling results, resource upgrade, and new pit model support the Directors decision to approve the plant expansion and the new Merrill-Crowe plant scheduled for delivery in October 2013."
MacPhersons will release a mining contracting tender documentation at its fully owned Nimbus project following the advancement in pit optimization studies.
The pit cutback in Year 1 will include four shallow pits with a focus on the oxide ore and the new gold zone and Lens 4, followed by the commencement of merger of the pits alongside the development of primary ore.
