In 2019, Greenstone Resources LP and International Base Metals Ltd entered into a strategic partnership to advance the Omitiomire Copper Project in Namibia through an earn-in agreement over Craton Mining and Exploration (Pty) Ltd.
The terms of the agreement include the requirement to complete a Bankable Feasibility Study with a minimum spend of USD 5m.
Total spend by Greenstone of USD9m to date, including USD4m on engineering studies for chloride heap leach and SXEW technology and USD1.3m on infill drilling. A comprehensive metallurgical test work programme is underway with Phase 4 results to finalise the BFS expected in Q3 2024.
Expected Outputs
Technical
- Production: 25-30ktpa Cu cathode
- Life of Mine: 13-15 years
- Preproduction capital: US$360m
- Ave LOM sustaining capital: US$10m p.a.
- Ave LOM opex: US$4,650/tonne copper
- Plant Capacity: 6.7 Mtpa
- Metallurgical recoveries: 80%
- Acid consumption: 10-15 kg/tonne
- Acid plant capacity: 250 tpd
- Leach cycle time: 200 days
- Mining Strip ratio: 4.8:1
- Based on Owner Mining
Financial
- Post-Tax NPV8: US$175m (100%)
- Post-Tax IRR: 18%
- Capital Intensity: 14,100/t Cu
- Key assumptions:
- Cu price $4.5 /lb LT
- FX: USD/ZAR 19:1
Valuation upsides not yet modelled include increased production/life of mine from reduced cut-off grade and increased reserve, and possible purchase of acid locally further reducing capex.
Geology
The Omitiomire Copper Deposit lies within the Kalahari Copperbelt. Geophysics and regional work have suggested an along-strike correlation of geology between Zambia, Botswana and Namibia. Some of the major copper deposits of northern Zambia, including Lumwana and Sentinel/Kalumbila, are associated with geological formations that share similarities with Omitiomire in the Damara Belt and other deposits in the Ghanzi-Chobe Belt such as Sandfire’s Motheo mine..
Deposit geology comprises two main rock packages:
- Mafic rocks, hosting the Cu mineralisation, mainly of quartz, plagioclase, dark biotite and amphibole. Mineralised banding up to 100m thick;
- Surrounding leuco-gneisses usually unmineralized, quartz, plagioclase, variable amounts of biotite and trace amounts of garnet and sphene.
Orebody strike length of 3.5km, open at depth
In 2023, Omico engaged the MSA Group to update the previous 2022 MSA resource to include the infill drilling undertaken by Omico in late 2022. The revised CIM Measured and Indicated resource is 81.2 million tonnes (‘Mt’) with 490 thousand tonnes contained copper at an average grade of 0.60% Total Copper, at a cut-off grade of 0.29% Cu. The resources are reported in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Best Practice Guidelines.