Slovak Operations
Known uranium mineralization in Slovakia is largely confined to Permian sedimentary and volcanosedimentary sequences. Historically, uranium was mined from a number of separate deposits in three ore fields developed in Permian sediments: one in western Slovakia near Trencin (in the Povazsky Inovec Mountains) and two in central Slovakia, south of Poprad (Kozie Chrbty Ridge) and south of Spisska Nova Ves (Spis-Gemer Ore Mountains).
Previous Exploration
Mining of uranium in Slovakia went into decline in 1980’s and ceased in 1990 as the result of the then low world price for uranium and for political reasons. Reliable figures for previous production from individual mines are not available and in some instances ore was shipped directly to the former Soviet Union rather than being treated in Slovakia.
Exploration for uranium by UPSS followed a set pattern involving vehicle-borne gamma surveys, ground gamma-ray spectrometer traversing, measurement of radon-in-soils, ground magnetic surveys, electrical prospecting methods, geological mapping, pitting, trenching and drilling. Airborne radiometric surveys were rarely carried out. The Kluknava and Zemplin Licences were selected to cover the geological sequences with the greatest potential for uranium as identified by the results of this previous exploration of much more extensive areas.
Vikartovce Licence
The Vikartovce Licence is one of four Uranium Exploration Licences which the company has applied for over areas of uranium mineralization in Slovakia; the remaining three applications are expected to be granted in the foreseeable future. Following these grants GB Energy proposes to commence detailed analyses of previous exploration data preparatory to formulating work programmes for all the licences which may include airborne radiometric and magnetic surveys.
GB Energy’s Vikartovce Licence is located in central Slovakia and covers an area of 88.4 sq km. It is situated close to and in the same favourable geology as the major historic uranium mines of Vikartovce and Kravany situated on the Kozie Chrby Ridge. Previous exploration identified a number of uranium anomalies and assessment of these will be a priority in the Company’s initial work programme.
Kluknava Licence
The Kluknava Licence covers a northwest-trending sequence of Permian sedimentary rocks bounded to the southwest by older crystalline rocks and overlain by younger sediments to the northeast. Uranium mineralization has been traced discontinuously at surface over a strike distance of 7km and it is confined to arkose units intercalated with sandstone, quartzite and volcanoclastics. Generally, the uranium is associated with thin quartz veins and limonitic alteration. Exploration stopped at a relatively early stage and only five exploration holes have been drilled in the current licence; these were drilled for geological mapping purposes and are spaced between 500m and1200m apart. Shallow trenches have tested five surface gamma anomalies ranging from 21 to 35 times background and from 100 to 400m in length and 100m in width. Uraninite and undifferentiated uranite have been identified as the main uranium minerals but as yet no assays have been located in the records for this area. Subsurface exploration is required to test the extent and tenure of uranium with depth.
Zemplin Licence
The Zemplin Licence is underlain by a structurally complex sequence of Palaeozoic and Mesozoic clastic sediments and Tertiary volcanics. This area has been subjected to more exploration than Kluknava including the drilling of 39 holes mainly to assist in understanding the geology and structure. One structural drill hole went to 1001.5m, 25 holes reached 500-600m depth, nine went to 300m and the remainder were drilled to about 150m. Uranium mineralization is stratabound in a polymictic conglomerate unit of Permian age. Where it crops out the conglomerate is 40m to 60m thick and where intersected in drill holes ranges from 3m to 50m thick; this observed variability in thickness is partly tectonic. Disseminated uranium mineralization is irregularly distributed over an extensive area and the mineralized sections are distinguished by a marked colour change in the host rock. The general tenor of the uranium mineralization encountered so far is in the order of 0.003-0.005% uranium. In one drill hole (Z0-10) a 2.1m intersection (300-302.1m) returned values of 0.061% uranium and 0.001% thorium.
