Since commissioning of the Chatree Mining Complex in November 2001, and up to June 30, 2013, the mine has produced over 1.3 million Oz of gold and over 5.8 million Oz of silver. For the year ended December 31, 2012, our cash operating costs rank us in the lower half of the global cost curve for gold producers, according to the Gold Survey published in April 2013 by Thomson Reuters GFMS. In the year ended June 30, 2013, we produced 133K Oz of gold at a total cash operating cost of US$767 per Oz after royalty.
Over the last 12 years, the Chatree Mining Complex's annual ore processing capacity has increased from a nameplate capacity of 1.0 million tonnes per annum in November 2001, to the current nameplate capacity of 5.0 million tonnes per annum as of November 2013. This sustained plant expansion is a result of our continuous streamlining of operations, combined with our debottlenecking initiatives which have seen an additional increase in capacity to 6.2 million tonnes per annum. We processed approximately 5.7 million tonnes of ore in the year ended June 30, 2013.
As at the end of April 2013, the Mineral Resource estimate at Chatree using 0.30g/t cut-off grade totals 4.03 million ounces of gold and 32.8 million ounces silver in 188.3 million tonnes of rock. The upgraded resource, including depletion from production to the end of April 2013, represents an increase of 356,000 ounces of gold and 2,162,000 ounces of silver when compared to the June 2012 Mineral Resource estimate for Chatree at the same cut-off grade.
Drilling continues within the mining lease targeting Inferred Resources that lie in close proximity to current pit designs.