Summary:
Karma is located in the Paleoproterozoic Baolé-Mossi domain of the West African Craton, specifically in the Birimian supracrustal rocks, which were probably developed upon a juvenile Paleoproterozoic crust (ca. 2.40-2.20 Ga).
Karma is situated in the regionally east-west trending Goren greenstone belt. The geology consists of a folded sequence of greywacke, siltstone, shale in the south-east and clastic, volcaniclastic and mafic volcanic rocks to the north-west. The western margin of the project area presents a broad north-south magnetic lineament that is interpreted as a first-order, crustal scale, sinistral, shear zone named the Ouahigouya Shear Zone (OSZ). The OSZ extends from the south into Boromo Greenstone Belt and branches in the Karma project into a series of north-east trending sub-shears reactivated during the Eburnean Orogeny between 2,130 and 1,980 Ma.
Substantial areas of Karma are covered by lateritic units, dominantly gravels and cuirasse, which form a highly indurated upper part of the lateritic regolith. A few lateritization events have resulted in weathering to depths of up to 120m. Laterites and sand cover limit the extent of bedrock outcrop in the project area and have limited the geological understanding of the region.
Seven mineral deposits at Karma have been defined up to now over the project area, namely, Kao, North Kao, GGII, GGI, Nami, Rambo and Yabonsgo deposits.
The Kao deposit is centered on a metric to pluri-metric thick mineralized structure oriented NW- SE which has developed along the footwall of a reverse fault within a deformed granodiorite to quartz-monzodiorite intrusive. It has 500m of strike-length and dips from 25° to 40-45° towards the NE where it remains open at depth. There are two sets of structures: (i) the dominant shallow east-dipping structure that extends the full length of the deposit in a north-west direction, which is transected by (ii) steeper, north to northeast-dipping set of thinner quartz veins that crosscut the north-west structure. The structures are weakly to intensely foliated, sericite- carbonate-silica altered and are host to multiple generations of quartz-carbonate-sericite- pyrite-arsenopyrite veining. Arsenopyrite with quartz veining generally correlate with higher gold grades.
The North Kao deposit hosted in the Kao intrusive was hidden under a thick laterite cover laying over approximately 60m of saprolite. It consists of a stacked sequence of structurally controlled tabular bodies, defined by pervasive quartz-sericite-pyrite alteration, breccia and locally distributed stockwork, shear and extensional veins. Gold is closely associated with each of these features. The main one striking north to NNW. A new second zone unmined yet, the Kao North Eastern extension, discovered in 2017 is located 500m to the east, running parallel the eastern edge of the Kao Intrusive over known strike length of 800m. It is still open to the south.
The GGI deposit has continuous lenses of gold mineralized rock over an East-West strike length of 2,100m. It consists of up to 10 discrete lenses, ranging from five to 40m thick, dipping near vertically.
The GGII deposit is like GGI, with an East-West strike length of 2,400m. There are three to five steeply dipping lenses along strike, with widths ranging from 5m to 30m. Higher grade steeply plunging shoots that occur at distinct flexures along strike are targets for deeper drilling.
The Rambo deposit comprises several relatively small mineralized lenses with the main zone containing a steeply plunging mineralized shoot. The deposit has an east-west strike length of approximately 450m and dips steeply to the South, along with a down-dip length of 230m. Thicknesses of the mineralized zones ranges from about 2.5 to 25m.
The Nami deposit is composed of three mineralized lenses with shallow dips of 20 to 25° toward the west-southwest. The strike length of the Nami deposit is about 550m, with a down-plunge extent of 300m, and a thickness of the mineralized zone ranging from about 2.5 to 30m. The deposit, which exhibits good continuity, is open to the west, north and south.
The Yabonsgo deposit is located along a regional NE striking shear zone and is defined over 600m inside a 1.3km long by 175m maximum width vertical porphyritic granodiorite body intruding an extensive meta-volcanosedimentary unit. The mineralization is related to a system of stacked flat to low-dipping quartz veins centered on the intrusive. The deposit is open at depth and shows discontinuous extensions toward the SW and NE directions along the shear zone.
The Karma deposits have characteristics of mesothermal, shear-hosted gold deposits associated with orogenic activity. Elements of stratigraphic control may result from mineralization/alteration being channeled along specific structural/lithological controls, such as competency contrasts between intrusive and sedimentary rocks that have affected porosity and fluid flow. The Karma deposits may be best described as structurally controlled, orogenic, hydrothermal deposits.
Production
Analysis of operations is only for the period up to its disposal by Endeavour on 10 March 2022. No mine operations data has been publicly available since Néré Mining SA acquired Karma mine on March 10, 2022.
The Karma Mine produced 10,246 oz of gold from 1 January 2022 to 10 March 2022.
| Commodity | Units | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 |
|
Gold
|
oz
| ....  | .... | 96,534 | 108,733 | 97,982 | 61,813 |
All production numbers are expressed as metal in doré.