Overview
Stage | Production |
Mine Type | Open Pit |
Commodities |
|
Mining Method |
|
Processing |
- Calcining
- Heap leach
- Carbon in column (CIC)
- Carbon adsorption-desorption-recovery (ADR)
- Elution
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
|
Mine Life | 11 years (as of Jan 1, 2018) |
Source:
p. 59, 77
Endeavour Mining Corp. owns a 90% interest in the Karma mine, with the remaining 10% owned by the Burkina Faso government.
As of April 26, 2016, True Gold Mining Inc. operates as a subsidiary of Endeavour Mining Corporation.
Riverstone Karma S.A. is a subsidiary of True Gold Mining Inc.
Summary:
As summarized by Thivierge (2008), much of the gold mineralization in the Ouahigouya district is either hosted by metasedimentary rocks associated with granodioritic to dioritic plutonic rocks or by the plutonic rocks themselves. The gold mineralization is associated with the presence of disseminated Fe-sulphide phases (mainly pyrite and/or arsenopyrite), quartz veining and hematitic alteration to epidotitic alteration. The evolution of the Goulagou, Rambo and Kao deposits appears to commonly involve the participation of syn-orogenic granodioritic plutonic masses. The Kao and Nami deposits occur within a plutonic body, the Rambo deposit occupies a plutonic contact zone, and the Goulagou I and II deposits occur peripheral to known or suspected plutonic masses. Smaller plutonic masses and dykes (diorite, quartz diorite and/or granodiorite) are present in the meta-sedimentary rocks and within the margins of the plutonic masses, and may represent structurally-controlled dyke networks associated with the carapace of the plutonic bodies. The development of progressive and retrogressive metamorphic minerals may be in part related to orogenic plutonism.
The Karma property deposits have characteristics of mesothermal, shear-hosted gold deposits associated with orogenic activity. Elements of stratigraphic control may result from mineralization/alteration being channelled along specific structural/lithological controls, such as competency contrasts between sedimentary and intrusive rocks, that have promoted porosity and fluid flow. The Karma deposits may be best described as structurally controlled, orogenic, hydrothermal deposits.
Robert et al.?s (2007) classification of orogenic gold deposits is restricted to deposits composed of quartz-carbonate veins and associated wall rock replacement, associated with compressional or transpressional geological structures such as reverse faults and folds. Orogenic deposits consist of variably complex arrays of quartz-carbonate veins that display significant vertical continuity, commonly in excess of 1 km, without any significant vertical zoning. The ores are enriched in Ag-As+/-W, with Au:Ag ratios >5. Other commonly enriched elements include B, Te, Bi, and Mo. The dominant sulphide mineral is pyrite at greenschist grade and pyrrhotite at amphibolite grade. Arsenopyrite is the dominant sulphide in many clastic-sediment-hosted ores at greenschist grade and loellingite (FeAs2) is also present at amphibolite grade. Mineralized zones are surrounded by carbonate-sericite pyrite alteration halos that are variably developed depending on host rock composition. At the regional scale a majority of deposits are spatially associated with regional shear zones and occur in greenschist-grade rocks, consistent with the overall brittle-ductile nature of their host structures.
Gold mineralization on the Karma property is controlled by shear-related veining and alteration, developed in two dominant geological environments: sediment-hosted and intrusive-hosted. Compilation, analysis, and evaluation of the exploration database have resulted in True Gold's identification of the Kao, Golden Arch, and Rounga mineralization trends on the Karma property.
Gold is strongly associated with silica sericite-carbonate alteration and veining. Sulphide minerals associated with mineralization consist predominantly of pyrite and arsenopyrite. A petrographic report by KCA (2011b) also identified minor amounts of chalcopyrite and covellite along with traces of bornite, chalcocite and sphalerite; however, these are rarely seen in hand specimen. Gold grains are generally less than 35 microns in size, with a low (about 1.5 weight percent) silver content, but may be as large as 300 microns and contain up to 20% silver (e.g. Rambo). Visible gold is known from all deposits but is not common. Gangue minerals of interest include clay, feldspar, quartz, dolomite, and hematite and goethite in the oxide and transition material. There is some carbon, at least a portion of which is organic.
Summary:
The mining method utilized will be conventional open pit mining, similar to that used at many other operations in Africa. Medium size mining equipment will be used (for example 90 tonne capacity haul trucks) to meet the production requirements.
Three types of material will be mined in the open pits. These are oxides, transition, and sulfide rock, with the oxides being the least competent rock and sulphides being the most competent. The oxides and some of the transition materials will not require blasting during excavation. However, as the pits deepen, harder rock will be encountered and some degree of drilling and blasting will be required.
Up to two hydraulic backhoe type excavators will be used as the primary loading units for the fleet of up to fourteen 90 tonne capacity haul trucks. A wheel loader will be available to be used in some instances. Waste dumps will be developed adjacent to all the pits, however at GGI some waste material may be placed in the mined-out pit area.
In some of the pits, minor amounts of "preg robbing" material may exist. Preg-robbing material contains components that absorb some of the gold released in the leaching process. It is assumed that this material will be stockpiled and processed at the end of the mine operational life to minimize its impact on the heap leach process.
Processing
- Calcining
- Heap leach
- Carbon in column (CIC)
- Carbon adsorption-desorption-recovery (ADR)
- Elution
- Solvent Extraction & Electrowinning
- Cyanide (reagent)
Flow Sheet:
Summary:
The proposed Karma process plant design will be based on gold heap leach technology, which will consist of two crushing circuits (for soft and hard ore respectively), agglomeration and stacking, heap leaching with cyanide solution followed by adsorption of the pregnant solution, elution and gold smelting. Services to the process plant will include reagent make up, storage and distribution, water and air supply.
The heap leach plant is required to process 4 Mtpa of oxide and transition ore for the recovery and extraction of gold, delivered from five separate open pit mines, namely: GGI, GGII, Kao, Rambo and Nami. Only a minimal amount of sulphides, extracted from Rambo and Nami pits, will be processed through the heap leach plant. Sulphide material from GGI, GGII and Kao cannot be treated through heap leaching due to its refractory nature.
There will be two separate crushing stations to treat the soft and hard ore. The soft rock circuit will be partially skid-mount ........

Recoveries & Grades:
Commodity | Parameter | 2019 | 2018 | 2017 | 2016 |
Gold
|
Recovery Rate, %
| ......  | ......  | ......  | ......  |
Gold
|
Head Grade, g/t
| 0.91 | 0.95 | 1.07 | 1.16 |
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Reserves at December 31, 2019:
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
3.1 Mt
|
Gold
|
0.85 g/t
|
84 koz
|
Probable
|
6.1 Mt
|
Gold
|
1.06 g/t
|
209 koz
|
Proven & Probable
|
9.2 Mt
|
Gold
|
0.99 g/t
|
293 koz
|
Measured
|
0.3 Mt
|
Gold
|
0.38 g/t
|
4 koz
|
Indicated
|
52.3 Mt
|
Gold
|
1.21 g/t
|
2,038 koz
|
Measured & Indicated
|
52.6 Mt
|
Gold
|
1.39 g/t
|
2,350 koz
|
Inferred
|
15.7 Mt
|
Gold
|
1.35 g/t
|
681 koz
|
Corporate Filings & Presentations:
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Aerial view:
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