Foto: Karakura hematite mine near Kabale in SW Uganda
Open pit or quarry for hematite on a steep slope, about 150 m long and 30–50 m wide. The hematite forms a concordant, rather steeply deposited layer within gray clay shales to clays, from which the hematite is sharply separated. Hematite forms lenticular deposits and belongs to the weakly metamorphosed sedimentary unit of the Akynyaru-Ankole Supergroup, whose age is Mesoproterozoic, about 1.6 Ga. The lenses are concordant with the layering of the sediments, indicating their sedimentary origin. The direction of the layer is E–W, the thickness is about 10 m, perhaps there is also a larger lenticular swelling. The hematite breaks up into large blocks that slide across the soft clay. Workers break them with sticks and also use fire. Further in the subsoil there is a position of sandstone under the clay. Very pure hematite is mined, there is little admixture. Hematite is a silvery gray, solid or fine-grained ore. In addition to massive hematite, there is a more rare occurrence of cavities with nice lenticular hematite crystals up to 1 cm. Impurities form quartz, sometimes also as 0.2–4 mm large, often bipolarly developed crystals in cavities. | Žáček, Vladimír | 2023