Sociedade Mineira do Luele S.A.'s shareholding structure comprises five entities:
• Taadeen Investment LLC (a subsidiary of the Oman Sovereign Wealth Fund) holds a 49% stake.
• Endiama, the state-owned company responsible for safeguarding the state's interests in activities related to the subsector in Angola, holds 44% of the capital.
• The remaining stakes are distributed among Reform (4%), Caixa de Catoca – Associação Mutualista (2%), and Instituto Geológico de Angola (IGEO), which holds 1%.
Summary:
The Luele (formerly known as Luaxe) deposit is located in the Lunda Norte Province of Angola.
According to preliminary studies of the geological potential, the Luele kimberlite is 600m deep, in an area of 105 hectares, with an ore quantity of 647 million tons that will result in 628 million carats.
The Luele kimberlite pipe is the largest among the deposits discovered over the last 60 years. It is already explored down to 400 meters. 26 xenoliths extracted from it’s core were nalyzed. Studied samples divided into the paragenetic groups, where the main and accessory minerals are presented. The overwhelming majority of samples are phlogopitized; half - contains amphibole, the third part - ilmenite. Attention is drawn to the large amount of titanium-containing minerals and the admixture of niobium in these minerals (Nb2O5 content (wt.%) in dark perovskite zones – 1.8, in white zones – 11, in zirconolite – 11). Crichtonite was found as an inclusion in clinopyroxine. The exotic sulfides – shandite (Pb2Ni3S2) and talcusite (TlCuFe0.6S2) – were detected at the same time like usuall sulfides of Ni, Fe, Cu. There was a vermicular zircon in one of the websterites. The exsolution lamellae were observed in some pyroxenes. Secondary minerals of silicates and oxides are serpentine and magnetite (hematite) of a wide range of compositions, often with various impurities.
The chemical composition of rock-forming minerals has some differences in comparison with similar minerals from the known diamondiferous pipes of Yakutia and South Africa. Garnets with a sharp and rare zoning are noted: 1) garnet of eclogite - chaotically spotted zoning of the whole grain on CaO-MgO-FeO (in wt.%: 4.8-8.6, 8.7-16, 14.8-21.5, correspondingly; 2) harzburgite garnet - strong heterogeneity of the edges with Al2O3-Cr2O3-FeO (in wt.%: 16.2-20.5, 2.4-9.9, 6.7-8.9, correspondingly). Olivine from chromite vherlites demonstrates strong spotted zoning (Mg# 86-92). Ilmenite from the olivine glimmerite has anomalously high TiO2 (57.86 wt.%) and MgO (18.79 wt.%). Ilmenite inclusion in serpentinized olivine from garnet-harzburgite contained a significant admixture of MnO (12.6 wt. %). On the whole, the compositions of the ilmenites of the studied parageneses show a good positive correlation between chromium and magnesium (R2=0.45). Wherlite's chromite was found in the form of regular ingrowths with phlogopite. The chromite, containing 54-63 wt.% of Cr2O3, practically did not detect in its composition Al2O3.
A distinctive feature of the investigated xenoliths can be considered their strong enrichment with alkalis, hydroxyl group, titanium, to a slightly lesser extent - calcium, zirconium, niobium, REE, thallium. Regular chromite-phlogopite ingrowths suggest the joint growth of these minerals, that is, the chromite of diamond association was formed under the conditions of the activity of the water-alkaline fluid. The zoning of many minerals speaks of abrupt changes in the conditions and environment of their formation. All this implies non-traditional scenarios for the formation of rocks block in the given section of the lithosphere.
Diamondiferous trend of the kimberlites in the Lunda region in Angola
The laying-out of the kimberlite pipes of Lunda region is under control of the massive circular structure of Saurimo diameter 200 km. In direction from NE to SW the average content of the diamonds in kimberlites increases 5 times – from 0,22 Ct/T (Kamafuka) to 1,10 Ct/T (Luele).