Diamba Sud (100%)
The Diamba Sud project covers 53.2km2 and lies within the highly prospective Senegal Mali Shear Zone orogenic belt. The Project is located 12km southwest of Barrick’s Loulo mine (12.5 million ounces) and only 7km west of Barrick’s Gounkoto mine (5.5 million ounces), both across the border in Mali.
Chesser acquired the Diamba Sud Project in 2017 and since then a large high-grade auger gold geochemical anomaly has been defined. Drilling to date has resulted in two shallow high-grade gold discoveries at Area A and Area D.
Extensive drilling has been undertaken on these discoveries to define the controls and size of these mineralised systems and a robust maiden mineral resource published in November 2021 containing 781koz @ 1.6g/t gold including ⁓500koz @ 3.0g/t gold. Chesser believes there is significant resource growth potential with resources open along strike and at depth.
Resource attributes include:
- High-grade ounces: 493koz @ 3.0g/t gold at a 1.5g/t cut-off or 692koz @ 2.0g/t gold at a 0.8g/t cut-off
- Shallow mineralisation: 95% of the ounces within 135m of the surface and 40% of the ounces occur within the near surface oxide mineralisation
- High confidence Resource: 69% of the ounces falling within the Indicated classification
- Robust Resources: 737koz falling within a US$1,500/oz gold price pit shell and 656koz falling within a US$1,350/oz gold price pit shell
- Significant Resource growth potential: mineralisation open along strike and at depth plus numerous exploration targets on the tenement
Figure 1: Diamba Sud plan view showing historical drilling, selected significant results, gold auger geochemical anomalies and target for drilling.
Figure 2: Diamba Sud Project Location.
Diamba Sud Mineral Resources
| Classification | Tonnes Mt |
Grade g/t Au |
Metal koz |
Total % |
|---|---|---|---|---|
| Indicated | 8.8 | 1.9 | 538 | 69% |
| Inferred | 6.4 | 1.2 | 243 | 31% |
| TOTAL | 15.2 | 1.6 | 781 | 100% |
Diamba Sud Mineral Resources
| Classification | Indicated | Inferred | Total | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Oxidation | Tonnes Mt |
Grade g/t |
Metal Koz |
Tonnes Mt |
Grade g/t |
Metal Koz |
Tonnes Mt |
Grade |
Metal Koz |
| Oxide | 3.7 | 2.2 | 262 | 1.3 | 1.2 | 50 | 5.0 | 2.0 | 312 |
| Fresh | 5.1 | 1.7 | 276 | 5.1 | 1.2 | 194 | 10.3 | 1.4 | 469 |
| Total | 8.8 | 1.9 | 538 | 6.4 | 1.2 | 243 | 15.2 | 1.6 | 781 |
Diamba Sud Grade/Tonnage within US$1,800/oz pit shell
| COG g/t Au |
Tonnes Mt |
Grade g/t Au |
Metal koz |
Indicated % |
|---|---|---|---|---|
| 0 | 60.1 | 0.5 | 933 | 65% |
| 0.3 | 20.1 | 1.3 | 842 | 67% |
| 0.5 | 15.2 | 1.6 | 781 | 69% |
| 0.8 | 10.9 | 2.0 | 692 | 71% |
| 1 | 8.6 | 2.3 | 628 | 73% |
| 1.5 | 5.2 | 3.0 | 493 | 80% |
| 2 | 3.4 | 3.6 | 393 | 84% |
Diamba Sud Mineral Resources within various US$/oz pit shells at COG 0.5g/t gold
| Pit US$/oz |
Tonnes Mt |
Grade g/t Au |
Metal koz |
Indicated % |
Strip ratio t:t |
|---|---|---|---|---|---|
| $1,350 | 11.2 | 1.8 | 656 | 75% | 2.7 |
| $1,500 | 13.7 | 1.7 | 737 | 72% | 2.9 |
| $1,800 | 15.2 | 1.6 | 781 | 69% | 3.0 |
| $2,000 | 16.0 | 1.6 | 802 | 67% | 3.0 |
Note
Resources reported within a US$1,800/oz gold price pit shell and at a cut-off grade of 0.5g/t gold
Figures are rounded and reported to appropriate significant figures to reflect the level of confidence
For full details refer to the ASX release dated 16 November 2021
Drilling, geochemistry and geophysics have identified numerous geochemical and structural targets on the Diamba Sud tenement, like Southern Arc, Area H, Line F and Western Splay, that will be the subject of ongoing exploration activities during 2022.
Diamba Sud shares the following four key characteristics to the neighbouring world class gold mines; Fekola and Gounkoto:
- High-grade gold associated with,
- Strong alteration in,
- Sedimentary host rocks, and
- Dominant structural control parallel to the splay of the main Mali Senegal Shear Zone.
Surrounding Diamba Sud, Barrick is undertaking extensive exploration on their Kabewest Project (Bambadji JV), 2-3km northeast of Area A and just over the tenement boundary. Kabewest mineralisation, alteration, structures, and host rocks appear identical to those at Area A. On the western tenement boundary AfriGold, a private enterprise, is mining on a semi-industrial scale their Karakaene 0.5Moz deposit which appears to be hosted within northwest trending structures.
50km to the south, IAMGold owns the 2.6Moz Boto Gold Project on which a positive definitive feasibility study has been completed and the Exploitation Permit was granted on 23 December 2020. IAMGold is also actively exploring in the region on their own ground or under joint venture with Oriole Resources on the Senala JV.
Area D
Area D oxide mineralisation forms a 20-40 m thick blanket of high-grade mineralisation, with gold mineralisation grading up to 100 g/t gold. Oxide mineralisation is bound to the SE by the NE trending fault that separates Area A and Area D. Oxide mineralisation trends in a NW direction possibly influenced by structures in that direction. Drilling to date has defined a strike length of over 400m in the NE-SW and NW directions.
Mineralisation below the high-grade oxide appears to be associated with two controls:
- The NE-SW trending fault exhibits as high-grade intercepts in brecciated mineralised sediments and has been intersected by a number of diamond drill holes along strike.
- A broad stockwork breccia zone in carbonate dominated lithologies, which act as a brittle definition zone and may also be influenced by the northwest structures.
The deepest drilling is only 150m vertical and additional drilling is required to fully understand the nature and extent of this mineralisation but represents a significant exploration target. The high-grade oxide mineralisation at Area D will supply very high margin, low strip ratio, free dig, ore feed for any future mining operation.
Area A
Area A, is a structurally controlled mineralised system with a NE-SW control being dominant. Two parallel mineralised structures have been defined to date. There is also a possible orthogonal NW-SE dilatational structure.
Mineralisation tends to favour the sedimentary units and there is only minimal oxide mineralisation at Area A.
Intense iron-carbonate alteration indicates significant fluid flow through the rocks and exhibits similar characteristics to other deposits on the Senegal Mali Shear Zone like Gounkoto and Fekola. The structures, alteration and host lithologies are identical to those being intersected by Barrick at their Kabewest prospect 2-3km along strike to the northeast. Mineralisation below the high-grade oxide appears to be associated with two controls.
Exploration activities undertaken on Diamba Sud
| Drilling Phases | Years | |
|---|---|---|
| Historical | Pre-2017 | RC drilling – 9 holes for 651m |
| Auger Drilling | 2018 | 3 Phases Phase 1. 400m x 100m – 1,651 holes Phase 2. 200m x 50m – 1,160 holes Phase 3. 400m x 25m – 75 holes |
| Phase 1 | 2019 | RC drilling – 70 holes for 4,671m |
| Phase 2 | 2019 | RC drilling – 26 holes for 2,873m IP Survey |
| Phase 3 | 2019-2020 | RC drilling – 24 holes for 2,535m Diamond drilling – 13 holes for 2,035m |
| Phase 4 | 2020 | RC drilling – 42 holes for 4,024m |
| Phase 5 | 2020-2021 | RC drilling – 110 holes for 15,452m Diamond drilling – 21 holes for 4,147m |
| Phase 6 | 2021 | RC drilling – 31 holes for 5,164m Diamond drilling – 34 holes for 4,393m |
| Phase 7 | 2021 | RC drilling 33 holes for 4,178m |
| Phase 8 | 2022 | RC drilling – 93 holes for 10,475m, Diamond drilling – 44 holes for 7,763m |
Regional Geology
The Diamba Sud exploration permit is located within the highly prospective Kédougou-Kéniéba Inlier which forms part of the Paleoproterozoic age Birimian Terrane of the West African Craton. Over 35 million ounces of gold has been discovered over the last 20 years within this inlier. The permit lies within the felsic volcanics and sediments of the Faleme Series, bound by the sediment-dominated Diale-Dalema Supergroup to the west and the SMSZ and the Kofi Series to the east.
The Faleme and Diale-Dalema supracrustal sequences are intruded by a series of variably deformed granitoid intrusions. Lithologies in the region are affected mainly by lower green schist grade metamorphism.