## 4 Results and Discussion
### Geochemical Variability of the Laterite Profile
#### 4.2.2 Limonite  
Based on the chemical analyses of laterite, two predominant types of the oxide ore and saprolite ore were distinguished. Oxide ore dominates in the upper part of the laterite profile. The oxide ore zone is equivalent to macroscopically distinguished levels of red and yellow laterite with an undisturbed structure and yellow laterite with a partly preserved structure. The major and trace elements concentrations in the horizons are given in Table 11.  
Goethite is the main nickel-bearing mineral in laterite ore (Table 4). Magnetite, maghemite, and hematite occur in smaller quantities. The occurrence of nickel is associated with goethite and less frequently with hematite. The Ni is absent in magnetite and maghemite. The Ni content of goethite ranges from 4.60-5.92 wt% (Table 5). In goethite, small amounts of Co and Cr are also present. Hematite has an intermediate composition between goethite and magnetite. In addition to iron minerals, Mn oxides (asbolane and lithiophorite) were found in some boreholes. They were mainly located in the lower part of the weathering profile, just above (at a depth of 7-8 m) the magnesium discontinuity zone. The Mn minerals are not thermodynamically stable. In a well-developed weathering profile, Mn is concentrated locally in iron oxides and does not form its own phases. The Mn oxides were analyzed using EPMA and are summarized in Table 6. The results indicate compositions between lithophore and asbolane. The NiO\({}_{2}\) content of Mn oxides ranges from 4.60-5.92 wt% and CoO (1.08-9.71 wt%). \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Minerals**} & \multicolumn{2}{c}{**Limonite**} & **Transition** & **Saprolite** \\ \cline{2-4}  & & **Average in wt\%, (Min–Max in wt\%)** & \\ \hline Goethite & 72.20 (10.70–91.17) & 50.84 (17.72–90.50) & 12.36 (2.01–77.00) \\ Magnetite/Maghemite & 5.69 (0.18–14.71) & 2.03 (0.17–4.23) & 0.00 \\ Hematite & 0.79 (0.00–6.93) & 0.00 & 0.00 \\ Cr-Spinel & 1.41 (0.00–3.27) & 0.71 (0.00–1.53) & 0.26 (0.00–1.06) \\ Gibbsite & 1.46 (0.00–4.68) & 0.48 (0.00–1.92) & 0.17 (0.00–1.10) \\ Bayerite & 0.86 (0.00–1.80) & 2.18 (0.00–6.72) & 0.00 \\ Serpentine Group Minerals & 5.59 (0.00–72.56) & 13.34 (0.00–28.43) & 64.28 (0.00–91.38) \\ Talc & 4.06 (0.00–10.35) & 5.15 (2.81–8.56) & 3.67 (0.00–18.07) \\ Quartz & 7.54 (0.00–30.21) & 13.84 (0.27–40.07) & 5.88 (0.16–19.62) \\ Amphibole & 0.13 (0.00–2.02) & 0.57 (0.00–1.61) & 1.43 (0.00–7.11) \\ Pyroxene & 0.00 & 0.00 & 0.68 (0.00–5.51) \\ Forsterite & 0.00 & 0.00 & 0.19 (0.00–2.13) \\ Smectite & 0.00 & 0.00 & 0.83 (0.00–9.12) \\ Chlorite & 0.25 (0.00–1.92) & 10.84 (0.00–33.89) & 9.56 (0.00–57-84) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Summary of mineral content in different horizons for selected boreholes. Quantitative phase analysis by XRD. The nickel content of this zone is in the range of 0.3 to 1.86 wt%, mean 0.8 wt% and Co up to 0.65 wt%, mean 0.13 wt%. Ni content is the lowest in this horizon compared to the other weathering horizons, although it increases with depth, while the Co content is the highest, especially in the lower part of the limonite horizon. In this level there is a high content of Fe\({}_{2}\)O\({}_{3}\) (23.04-76.17, mean 55.55 wt%), Al\({}_{2}\)O\({}_{3}\) (2.52-20.52, mean 9.56 wt%). The average content of chemical components is as follows: SiO\({}_{2}\) (13.93 wt%), MgO (3.86 wt%), Cr\({}_{2}\)O\({}_{3}\) (2.93 wt%), MnO (1.05 wt%), and TiO\({}_{2}\) (0.16 wt%). Very low contents form ZnO up to 0.09 wt% and Sc\({}_{2}\)O\({}_{3}\) up to 0.01 wt%. The abundance of trace elements Ba (3-880 ppm), Cu (60.0-110.0 ppm) and V (109.0-171.0 ppm), shows variable values. Ga (4.0-6.0 ppm) and Ge (2.5-4.0 ppm) are present in small amounts. The contents of other elements do not exceed normally the lower detection limit of the test method used (ICP-MS and WDXRF). In the upper part of the laterite, there has been no significant enrichment in rare earth elements. As with REE, no enrichment was found in PGM.