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The porosity of the pyrolyzed oil shale ore bed is between 23 and 31%.
Hydrothermal underwater springs deposited the mercury in littoral swamps forming the synsedimentary ore beds and lenses in the black Skonca shales and tuffs of the Ladinian age (Mlakar, 1974; Placer, 1976).
The mineralisation tends to be confined to two ore beds, each varying from 5 m to 15 m in thickness and separated by a 25 m deep layer of siliceous dolomite.