Overview
| Stage | Production |
| Mine Type | Open Pit |
| Commodities |
|
| Mining Method |
|
| Production Start | ...  |
| Mine Life | 2031 |
Source:
p. 53
| Company | Interest | Ownership |
|
Government of Guinea
|
15 %
|
Indirect
|
|
Nord Gold plc
|
85 %
|
Indirect
|
|
Societe Miniere de Dinguiraye SA
(operator)
|
100 %
|
Direct
|
The mine was acquired by the Company at the end of July 2010, as part of the Crew Gold Corporation acquisition. The Company holds Lefa through Crew Gold Corporation Ltd (in which the Company has a 100% interest), which in turn holds an indirect 85% interest in Société Minière de Dinguiraye S.A. (“SMD”), which owns Lefa. The remaining 15% of shares in SMD are held by the Guinean government.
Contractors
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Deposit Type
- Breccia pipe / Stockwork
- Vein / narrow vein
Summary:
The Lefa gold mine lies within the Siguiri Basin, part of the Paleoproterozoic Birimian terrain of the West African Craton. Host lithologies are typically Paleoproterozoic (2.2-2.1 Ga) volcanosedimentary greenstone belts, metamorphosed to greenschist facies (or higher) and intruded by felsic plutons. Deformation is associated with a system of NE-SW trending crustal-scale ductile shear zones, related to the Eburnean orogeny, a protracted series of orogenic events spanning 2.2-2.0 Ga. These deformation zones are considered fundamental to the development of gold mineralisation.
Localised finely-laminated white and pale yellow limestones occur towards the north of the licence. Three post-Birimian sedimentary packages occur within the Lefa area, namely:
- Neoproterozoic fluvial and shallow marine sandstones;
- Eocene paleo-valley fill loosely consolidated sandstones; and
- post Post-Eocene transported colluvium.
Intrusive lithologies within the basin consist of basic to intermediate sheet intrusives and the Maléa intrusion. Two sets of dykes are identified, corresponding to a swarm which exhibits trends of circa 105-285° and 055-235°. In addition to the dykes, the basin is also intruded by numerous dolerite sills ranging from a few metres to tens of metres in thickness.
Mineralisation at Lefa is hosted within the “Lefa Corridor”, which lies within the Siguiri Basin. This is a zone which is some 10 km wide, underlain by an upper clay ........
Summary:
The Lefa gold mine operates a typical modern open pit operation with drilling and blasting followed by load and haul allowing for selective mining of the ore. The material lithologies are divided into four main categories Saprolite, Laterite, Transition and Fresh. Saprolite and Laterite are also referred to in combination as oxide material. SMD has taken over the ownership and operation of the mining fleet as well as undertaking the mine planning, scheduling, grade control, surveying and quality control.
The current fleet capacity is sufficient, with only rebuilding and some replacement capital necessary over the remaining period of the Base Case LoMp to Q1 2030.
Current mining operations at Lefa are focused on various open pits. Total planned mining production, as per the Base Case schedule, from 2021 onwards is approximately 36 Mtpa going down to 28 Mtpa from 2025 to 2028 after which it tapers down to the end of the LoM in 2031.
The Company has commenced studies relating to underground mining beneath the main Lero-Karta open pit.
Open Pit Geotechnical Considerations
The Lefa gold mining complex in Guinea is formed of a number of open pits of varying degrees of maturity. The largest open pit is the Lero-Karta-Camp de Base operation which is the main source of ore and mines both oxide and fresh material. The Fayalala, Banko, Kankarta and Firifirini open pits also mine oxide and transition/fresh material while the remainin ........
Source:
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Source:
Summary:
- subscription is required.
Production:
| Commodity | Units | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|
Gold
|
koz
| ...... | ...... | ...... | 188 | 209 | 195 | 214 |
All production numbers are expressed as metal in doré.
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Operational Metrics:
| Metrics | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|
Total tonnes mined
| ...... | 41.1 Mt | 38,155 kt | 34,539 kt | 26,473 kt | |
|
Ore tonnes mined
| ...... | 6,755 kt | 6.69 Mt | 6.46 Mt | 6,137 kt | 6,019 kt |
|
Waste
| ...... | 34.4 Mt | 31,466 kt | 28,076 kt | 20,336 kt | |
|
Stripping / waste ratio
| ...... | 5.09 | 4.7 | 4.34 | 3.31 | 3.15 |
|
Tonnes processed
| ...... | 6.03 Mt | 6,181 kt | 6,911 kt | 6,599 kt | 6,558 kt |
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Reserves at December 31, 2020:
Cut-off grades for resources range from 0.27 to 0.48 g/t Au for open-pit and are 1.4 g/t Au for underground.
Cut-off grades for reserves range from 0.3 to 0.6 g/t Au depending on deposit.
| Category | OreType | Tonnage | Commodity | Grade | Contained Metal |
|
Proven
|
In-Situ (OP)
|
0.181 Mt
|
Gold
|
0.9 g/t
|
6 koz
|
|
Probable
|
Heap leach
|
5.659 Mt
|
Gold
|
0.6 g/t
|
109 koz
|
|
Probable
|
Stockpiles
|
6.8 Mt
|
Gold
|
0.6 g/t
|
124 koz
|
|
Probable
|
In-Situ (OP)
|
32.571 Mt
|
Gold
|
1 g/t
|
1.042 koz
|
|
Probable
|
Total
|
45.029 Mt
|
Gold
|
0.9 g/t
|
1,275 koz
|
|
Proven & Probable
|
Heap leach
|
5.659 Mt
|
Gold
|
0.6 g/t
|
109 koz
|
|
Proven & Probable
|
Stockpiles
|
6.8 Mt
|
Gold
|
0.6 g/t
|
124 koz
|
|
Proven & Probable
|
In-Situ (OP)
|
32.751 Mt
|
Gold
|
1 g/t
|
1,048 koz
|
|
Proven & Probable
|
Total
|
45.21 Mt
|
Gold
|
0.9 g/t
|
1,281 koz
|
|
Measured
|
Total
|
0.309 Mt
|
Gold
|
1.25 g/t
|
12 koz
|
|
Indicated
|
Total
|
94.078 Mt
|
Gold
|
1.02 g/t
|
3,083 koz
|
|
Measured & Indicated
|
Total
|
94.387 Mt
|
Gold
|
1.02 g/t
|
3,095 koz
|
|
Inferred
|
Total
|
26.137 Mt
|
Gold
|
1.62 g/t
|
1,365 koz
|
|
Total Resource
|
Total
|
120.524 Mt
|
Gold
|
1.15 g/t
|
4,460 koz
|
| Type | Material | Diameter | Length | Description |
Heavy Mobile Equipment as of March 1, 2021:
| HME Type | Size | Quantity |
|
Truck (haul)
|
100 t
|
.......................
|
|
Truck (haul)
|
40 t
|
.......................
|
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Corporate Filings & Presentations:
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