The Perkoa Mine and the 2,000 tonne per day milling operation is located in the Sanguie Province, approximately 120 kilometres west of the capital city of Ouagadougou, Burkina Faso. The Perkoa Mine has been in commercial operation since 2013 and currently produces a zinc concentrate.
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-aged rocks in Burkina Faso are the same sequences that host major gold deposits in Burkina Faso and in the neighbouring countries of Ghana and Mali. The Birimian Supergroup of West Africa is renowned for their gold mineralization; however, known occurrences of base metals are scarce. The Perkoa deposit represents the only significant zinc-silver massive sulphide mineralization discovered in the Birimian to date and it is also the first zinc-silver 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 zinc-silver mineralization has been dated at 2.12 to 2.14 billion years ago.
In the Perkoa 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 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 Mineral Resource Estimates
Perkoa Mineral Reserves as at December 31, 2017(1, 2)
Zn M lbs
Proven & Probable
(1) All mineral reserves have been estimated in accordance with the CIM Definition Standards. Numbers may not add due to rounding. The mineral reserve is shown at 100% ownership; Trevali holds a 90% joint venture interest in the Perkoa mine.
(2) The Perkoa Underground Mine mineral reserve estimate is reported based on planned stopes with an net smelter return cut-off-value of US$100/tonne with incremental stopes greater than US$80/tonne included based on individual financial analysis, metal prices of: US$1.20/lb zinc, FX: €/US$1.08. The Perkoa Underground Mine mineral reserve has been prepared by the mine engineering department of the Company with an effective date of December 31, 2017 and has been reviewed and approved by Professional Engineer Torben Jensen (P.Eng.), a consultant with Roscoe Postle Associates Inc., who is an independent Qualified Person as defined in NI 43-101 and will be detailed in the technical report entitled “Technical Report on the Perkoa Mine, Burkina Faso” to be dated April 12, 2018, which will be available under the Company’s profile on SEDAR at www.sedar.com within 45 days.
Perkoa Mineral Resources as at December 31, 2017(1, 2)
Zn M lbs
Measured & Indicated
(1) All mineral resources have been estimated in accordance with the CIM Definition Standards. Mineral resources are inclusive of mineral reserves. Mineral resources that are not mineral reserves do not have demonstrated economic viability. Numbers may not add up due to rounding. The mineral resource is shown at 100% ownership, Trevali holds an 90% joint venture interest in the Perkoa mine.
(2) The Perkoa Underground Mine mineral resource estimate is reported based on 5% zinc cut-off grade with metal prices of: US$1.20/lb zinc, FX: €/US$1.08. The Perkoa Underground Mine mineral resource estimate has been prepared by the mine geology department and non-independent technical consultants to the Company with an effective date of December 31, 2017 and has been reviewed and approved by Consulting Professional Geologist Ian Blakley (P.Geo.), a consultant with Roscoe Postle Associates Inc., who is an independent Qualified Person as defined in NI 43-101 and will be detailed in the technical report entitled “Technical Report on the Perkoa Mine, Burkina Faso” to be dated April 12, 2018, which will be available under the Company’s profile on SEDAR at www.sedar.com within 45 days.
Perkoa Production Statistics(3)
Q1-2018 Preliminary Production
Average Head Grades:
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Average Recoveries (%):
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(3) Trevali acquired ownership (90%) of Perkoa on August 31, 2017.
2018 Production Guidance(4)
2018 Zinc Production
(million lbs payable)
Annual Site Operating Cost Guidance (per tonne)
(4) Production guidance presented on a 100% basis, Trevali owns 90% of Perkoa. Constitutes forward-looking information; see “Cautionary Note Regarding Forward-Looking Statements”.