An Underground Scoping Study has been undertaken providing an assessment of the potential for an underground development phase for the Makabingui Gold Project within the one million ounce gold resource. Underground development would commence on Completion of Pit 1 mining operations and utilise existing infrastructure and 300ktpa processing plant factored into the Open Pit Feasibility Study for the development of four high grade open pits.
Makabingui High Grade Underground Scoping Study highlights at US$1200/oz gold price:
| Mined ounces | 120,000 ounces (additional to open pits) |
|---|---|
| Average gold grade to the mill | >7.0 g/t gold |
| Mine life extension | ∼2.5 years |
| Estimated Revenue | US$144M |
| Estimated OPEX | US$56M |
| Estimated CAPEX | US$35M |
| Processing recovery | 95% |
| Cut-off-grade | 3g/t gold |
The pit designs for Pit 1, developed as part of the initial mining phase of the Makabingui Gold Project, have been used for the preliminary Underground Scoping Study. The underground analysis only uses the Inferred Resources within the vicinity of Pit 1 (see Figure 1 & 2).
Figure 1. Mine Plan View Showing Pits and Waste Dump
Figure 2. Makabingui Resource Blocks – Pit 1 Area
The Makabingui gold resource at depth comprises steep mineralised zones dipping to the south east and striking NNE. The following parameters have been used to generate optimised stope shape designs within the mineralised lodes:
| Minimum mining width (horizontal) | 2 metres |
|---|---|
| Stope height | 20 metres |
| Stope length | 10 metres |
| Stope dilution (on both footwall and hangingwall) | 0.3 metres |
| Minimum pillar between adjoining stopes (between lodes) | 10 metres |
| Cut-off-grade | 3g/t gold |
The Pit 1 design, prepared as part of the Open Pit Feasibility Study, was used to locate the portal. The underground design used the following parameters:
| Decline size 5 metres wide by 5.5 metres high at a gradient of 1 in 7 | 2,120 metres |
|---|---|
| Lateral access of 5 metres wide by 5 metres high and flat | 3,740 metres |
| Mineralised lode development of 4.5 metres wide by 4.5 metres high and flat | 3,360 metres |
| Interval between levels | 20 metres |
| Ventilation development | 734 metres |
Figures 3 & 4 below show the underground design.
Figure 3. Underground Development Design Looking South East
Figure 4. Underground Development Design Looking South East Including Stopes
Underground development would commence on completion of Pit 1 mining operations and utilise existing infrastructure and 300ktpa processing plant factored into the Open Pit Feasibility Study for the development of four high grade open pits.
Figure 5. Project Layout – Mine and Processing Plant