Orezone Gold has reported positive results for an NI 43-101 compliant preliminary economic assessment (PEA) of its Bomboré gold project in central Burkina Faso, West Africa. The PEA evaluated two near-surface, open-pit development scenarios—heap-leach and carbon-in-leach (CIL)—and demonstrated both are potentially economically feasible if inferred resources can be substantially upgraded to indicated and more extensive technical studies confirm the preliminary information available for the study. Based on the results of the PEA, Orezone has approved a $24-million drilling and feasibility budget for 2011-2012 and is moving forward with a target for production in 2015.
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.