Numerous occurrences of Mo-W mineralization were found in the zones of Late Carboniferous granitoid intrusions in the Sudety Mts, but no concentrations of economic importance have been found so far in this area. Molybdenium forms different genetic types of deposits which usually occur separately. Most important are porphyry type deposits (Mo-, and Cu-Mo- subtypes) and less important are skarns, greisens, hydrothermal veins, weathered and Mo-bearing sediments.
The Myszków deposit of molybdenium-tungsten ores with copper is situated at north-eastern margin of the Upper Silesian Coal Basin (map), in the contact zone of the Małopolska Block and Upper Silesian Block separated by the Hamburg-Cracow tectonic zone. The deposit is of the Mo-W-Cu porphyry type. Its ore mineralization is of the stockwork type, forming a system of quartz veins with ore minerals sulfide and oxide related to Variscan igneous activities. Intensive drilling program from the years 1975-1992 made possible detailed exploration of the Myszków deposit in area of 0.5 km2 and down to the depth of 1,300 m. The exploration carried out in 1993 allowed to estimate inferred resources of the Myszków in the Polish C2 resources category (documentation prepared by Polish Geological Institute). Anticipated economic resources of ores occurring at the depth down to 1,000 m were estimated at about 380 million tonnes, with 0.23 million tonnes of Mo, 0.18 million tonnes of W and 0.55 million tonnes of Cu and mean content of Mo and W equal 0.049% and 0.041%, respectively.
In 2007 the economic resources of the Myszków deposit were re-evaluated to find that they are markedly larger than previously estimated, exceeding 550 million tonnes of Mo-W-Cu ores. Anticipated economic resources of the deposit were estimated at about 0.295 million tonnes of Mo, 0.238 million tonnes of W and 0.8 million tonnes of Cu, and anticipated subeconomic resources – at 0.298 million tonnes of Mo, 0.212 million tonnes of W and 0.771 million tonnes of Cu. The Myszków ores have not been exploited so far. It should be added that according to the available data there are high chances for discovery of other deposits of Mo-Cu porphyry ores with tungsten in the contact zone of the Małopolska Block and Upper Silesian Block.
Molybdenium co-occurs with other metals in the ores of the porphyry type mentioned above as well as in the stratabound copper deposits in the Fore-Sudetic Monocline and coal deposits in the Upper Silesian Coal Basin. However, the applied technological processes are not aimed at separation of this metal.
Prepared by: Stanisław Z. Mikulski