The pit shells hosting the current resources occur in several zones over a distance of 11 km; are based on an average drill depth of 60 m; and exhibit 35,000 oz of gold per vertical meter above a cut-off of 0.35 g/mt gold. The PEA is based on an estimated 60.9 million mt of indicated mineral resources at a grade of 0.81 g/mt, for 1.6 million oz of gold, plus 60.6 million mt of inferred mineral resources at a grade of 0.96 g/mt, for 1.9 million oz. The CIL scenario is based on the indicated and inferred resources in saprolite, transition or saprock, and fresh rock. The heap-leach scenario is limited to the saprolite and transition resources because the fresh rock indicates relatively poor heap-leach gold recoveries.
The base case financial models for both scenarios used a gold price of $1,100/oz and a Brent crude oil price of $80/bbl. The heap-leach scenario assumes a total mining rate of 18 million to 20 million mt/y and a rate of ore placement on the leach pad of 5.8 million mt/y. The larger CIL scenario calls for a total mining rate of 38 million to 39 million mt/y to supply 9.3 million mt/y to the mill. Total gold production over a 10-year mine life is estimated at 949,000 oz for the heap-leach scenario and 2.2 million oz for the CIL scenario. Initial capital cost estimates are $204.7 million for the heap-leach scenario and $499.5 million for the CIL scenario.
Orezone expects to complete a 170,000-m drill program, more detailed metallurgical testing, a full social impact study, and other critical path engineering items by the first quarter of 2012. Although expansion drilling will likely continue, a resource update will be performed early in 2012, targeting completion of a full feasibility study in the third quarter of 2012. The full feasibility study may include a combination of the heap-leach and CIL scenarios as part of a multi-phase project.