Rio Tinto announces a 730,000 tonne increase of contained copper in mineral resources at Kennecott Utah Copper

 

Rio Tinto has increased its copper mineral resources by 20 million tonnes to 106 million tonnes at its wholly-owned Kennecott Utah Copper Bingham Canyon Mine. The mineral resource addition, known as the North Rim Skarn, increases contained metal in mineral resources by 0.73 million tonnes copper, 1.0 million ounces gold and 13 million ounces silver over the 2010 year-end mineral resource estimate. A full summary of the updated Bingham Canyon mineral resource estimate is provided on page 2.

The North Rim Skarn is a high-grade copper-gold skarn deposit located approximately 300 metres below the current Bingham Canyon pit and is expected to be developed by underground methods. This deposit was initially explored by a surface and underground drilling programme that was completed in the mid-1980s. Further surface drilling has more recently been completed with the combined data set of 35 surface and 71 underground drill holes (total lengths of 39,127 metres and 13,001 metres, respectively) forming the basis for this new resource estimate.

Andrew Harding, chief executive, Rio Tinto Copper said “While establishing this high grade underground resource at Kennecott Utah Copper is substantial in itself, it points the way to the significant underground potential of the asset.”

Rio Tinto has committed US$165 million to complete the next stage of exploration and development studies by 2014. This pre-feasibility programme includes final shaft rehabilitation, an access decline from the pit and further underground exploration drilling. This investment follows the approval for US$238 million to advance studies extending the open pit life to 2028 and the purchase associated long-lead time equipment.

Mineral resource estimates at Bingham Canyon Mine have been generated to comply with the JORC code guidelines. The table below compares the new mineral resource estimate as classified and the 2010 year-end mineral resource estimate. Mineral resources for the open pit exclude ore reserves and remain unchanged from those reported at 2010 year-end.