Geologiczne podstawy klasyfikacji bloczności złóż kamieni budowlanych

Jan Bromowicz, Andrzej Karwacki



The paper presents the results of studies on methodology of estimating block separateness of rock raw material deposits (2 - 3). The block separateness index "b", defining volume share of rock material divided into blocks in a given deposit, is established for various types of rock and an attempt to classify building rock deposits is made (Table).
The block separateness of rocks is determined by several geological phenomena. A genetic type of rock raw material is of some importance here. In the case of granitoids, block separateness is closely related to geological setting and internal structure of a deposit. Deposits characterized by simple structure display regular separateness systems and homogeneous quality of raw material. This results in very high values (30-80% of volume) of block separateness indices. Granitoid deposits with complex structure are characterized by markedly smaller possibilities to obtain blocks (5-20%). Among the surveyed granitoid deposits with simple structures, the share of those characterized by intermediate block separateness equals 40% and that of deposits characterized by high separateness - 60%, whereas in the case of deposits with complex structure, the share of those with intermediate separateness equals 50% with low separateness - 14% and high separateness - 36%.
Sandstone deposits of both platform and geosynclinal types are characterized by similar indices as granitoid deposits with simple structure (Table). Indices obtained for limestone and dolomite deposits appear similar to those of sandstone deposits but they are often reduced due to karst processes. In the case of marbles, overprinting of planes of different origin and age results in low values of the . indices, usually below 5% of deposit volume.

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