2.6. Vítkov II uranium deposit

Group with intercalations of quartzites, amphibolites, calc-silicate rocks and crystalline limestones. Uranium mineralisation is associated with N-S trending zones of the Zadní Chodov fault in areas of their intersection with NW-SE trending fault structures. The shear zones are infilled

The thickness of main mineralised shear zones (CH-1, CH-4 and CH-11) ranges from 30 cm to approximately 1–2.5 m. Their total thickness is about 50–150 m (Figure 4). The high-grade uranium mineralisation was developed at the depths of 440–960 m beneath the present surface. The most common uranium minerals are coffinite (65 vol.%), uraninite (25 vol.%) and brannerite (10 vol.%). Total mine production of the Zadní Chodov uranium deposit was

The Dyleň uranium deposit was located in high-grade metasediments of the Moldanubian Zone (migmatised biotite, biotite-sillimanite and quartzitic paragneisses with intercalations of quartzites). The main tectonic zone in the area of the Dyleň ore deposit is N-S trending zone of the Dyleň fault, dip to W at an angle of 60–70. However, the uranium mineralisation is associated with NW-SE trending shear zones, dip to SW at an angle of 70–90. The W-E striking faults crosscut both shear zone structures. All these shear zones and faults are infilled by chlorite-enriched aceites. Highly disseminated apatite-brannerite-coffinite association with up to 90 vol.% of coffinite represents the Variscan uranium mineralisation. Main part of uranium mineralisation is bounded on highly altered biotite paragneisses. Total mine production of the Dyleň uranium deposit was

4150.7 tons U with average grade of 0.195% U, mined from 1952 to 1992 [8].

1100.5 tons U with average grade of 0.14% U, mined from 1965 to 1991 [7].

Figure 4. Schematic cross section of the Zadní Chodov uranium deposit, modified from [8].

by highly chloritised and arigilitised host rocks.

54 Uranium - Safety, Resources, Separation and Thermodynamic Calculation

2.5. Dyleň uranium deposit

The Vítkov II uranium deposit occurs in the central part of the Bor pluton. Its main mineralised shear zones are zone 0–30 in the east and the Vítkov zone in the west. The thickness of the shear zones varies from 5 to 7 m to several tens of metres. Both the shear zones are infilled by crushed altered rocks, quartz and carbonates. Rich accumulations of U-minerals often occur in their vicinity. The pennate NW-SE faults evolved between both shear zones are infilled by dykes of biotite and two-mica granites and aplites. Granites of the Bor pluton in the area of the Vítkov II uranium deposit are usually intensely altered to aceites. The ore bodies comprise coffinite, uraninite and brannerite finely disseminated in the surrounding altered granites. The ore bodies are grouped into four ore pipes, which are accumulated in environs of the shear zone 0–30. Total mine production of the Vítkov II uranium deposit was 3972.6 tons U with average grade of 0.124% U, mined from 1961 to 1990 [7].

## 2.7. Lhota uranium deposit

The Lhota uranium deposit is situated in the central block of the Bor pluton. Uranium mineralisation is evolved in altered coarse-grained biotite granites, accompanied by smaller bodies of amphibole-biotite granodiorites and tonalites. All these granitoids are overlain by remnants of the Moldanubian high-grade metasediments. The NW-SE, partly also N-S trending aplite dykes, pierces this rock complex. The two ore bearing shear zones (Os-2 and Os-17) strike NW-SE and dip steeply NE. The thickness of these mineralised shear zones are 5– 18 m. The mineralised shear zones comprise coffinite and brannerite.

This uranium deposit has been verified between 1953–1967 and 1975–1989 by five exploration shafts down a depth of 250 m and by numerous boreholes down to levels of 300–600 m. During these two exploration stages, uranium mineralisation with the total amount of 158 t U and average grade of 0.120% U was identified [7].
