Perkoa Zinc Mine
The Perkoa underground zinc mine and 1,800-1,900 tpd milling operation is located in the Sanguié Province, 120 km west of the capital city of Ouagadougou, Burkina Faso. The Perkoa mine has been in operation since 2012 and currently produces zinc concentrates.
Geology and Mineralization
The Perkoa deposit lies in a felsic to intermediary series of volcanic and volcanoclastic rocks, within the Paleoproterozoic Birimian Supergroup of West Africa. The prospective Birimian rocks in Burkina Faso are the same sequences that host major gold deposits in Burkina Faso and in neighbouring Ghana and Mali. The Birimian greenstone belts of West Africa are renowned for their gold mineralization, however, known occurrences of base metals are scarce. The Perkoa deposit represents the only significant Zn-Ag massive sulphide mineralization discovered in the Birimian to date and it is also the first Zn-Ag massive sulphide mineralization discovered in this region.
The Perkoa project area is located in the central part of the Boromo greenstone belt, which comprises volcanic and sedimentary rocks of the Lower Palaeozoic Birimian Supergroup that have been metamorphosed to lower greenschist facies. At least three phases of deformation have affected the Boromo belt and mafic to felsic dykes and granitic bodies were emplaced in several intrusive phases. The Zn-Ag mineralization has been dated at 2,120 Ma to 2,141 Ma (Billiton, 1998).
In the Perkoa mine area, the Birimian sediments, lavas, and pyroclastics strike from northeast to southwest and generally dip steeply to the northwest. Several units of andesitic lavas with subordinate andesitic tuffs, separated by sequences of tuffs interlayered with fine grained clastic sediments, make up the lithological package in the project area.
A number of syn-tectonic and post-tectonic intrusive bodies have been emplaced within the meta-sediments, which range from large plutons of granitic and dioritic composition, to smaller ultramafic to rhyolitic intrusions. Crosscutting lineaments with a northwest-southeast orientation are common although major displacements along these lineaments are rare.
The Perkoa deposit has been classified as a volcanogenic massive sulphide (VMS) deposit. VMS deposits are lenses and sheets of massive sulphide that form from seafloor hydrothermal systems where metal rich fluids (black smoke) precipitate on (exhalative) or near the seafloor (sub-seafloor replacement.).
The Perkoa mineralization occurs as a series of stacked, northeast-southwest striking tabular VMS lenses hosted, and separated by, tuffaceous material that has been overturned with an average dip of approximately 70°. The deposit is unusual for its high concentrations of zinc and barium mineralization, and relatively low levels of lead and copper.
Mineral Reserve and Resource Estimates
Mineral reserves and mineral resources in above table derived from the technical report entitled “Technical Report on the Perkoa Mine, Burkina Faso” dated April 7, 2017 and effective December 31, 2016 prepared by Roscoe Postle Associates Inc.; CIM definitions were followed for Mineral Reserves and Resources; Mineral Reserves are estimated at an NSR cut-off value of $100/tonne inclusive of capital expenditure, incremental stopes greater than US$78/tonne are included based on individual financial analysis; Mineral Reserves are estimated using an average consensus forecast zinc price of US$0.99 per pound and a €/US$ exchange rate of 1.11; Shown at 100% ownership; Mineral Resources are inclusive of Mineral Reserves; Mineral Resources are estimated at a cut-off grade of 5% Zn; Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability).
Please refer to Disclaimer for important items relating to the resource estimates and production plans.
Perkoa Production Statistics
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2017 Production Guidance (based on 100%)
Zinc – 165-170 million payable pounds