Spękania w utworach mioceńskich południowego obrzeżenia Gór Świętokrzyskich i możliwość ich wpływu na otworową eksploatację złóż siarki

Abstract

FRACTURES IN MIOCENE STRATA OF THE SOUTHERN MARGIN OF THE HOLY CROSS MTS AND ITS INFLUENCE ON THE HOT-WATER UNDERGROUND EXPLOITATION OF SULPHUR DEPOSITS Summary The authors carried out studies on the tectonics of Miocene strata in the areas of Pinczów, Busko Zdrój, Wiśniowa and Chmielnik since 1972. The studies have shown a high regularity in orientation and similarity of the nature of fractures in Lower Tortonian limestones, gypsum series, and detrital Sarmatian deposits in the whole region. Percentage graphs of directions of fractures revealed two preferred directions: one sub-longitudinal, with a maximum in the interval 155 °-175 °, and another sub-latitudinal, with maximum in the interval 85° 95 °. The data obtained were compared with results of previous studies (4, 8) and with the data concerning the tectonics of sulphur-bearing Tortonian series from the area of Grzybów. In the latter area the Tortonian sulphur is exploited by hot-water underground mining techniques. Microgravimetric and geodetic surveys of terrain surface deformations in the mining field suggest the existence of long sub-latitudinal fractures cutting the sulphur-bearing limestone layers. This is indicated by the shape of subsidence basins over exploited parts of the deposit, as well as by the fact that the sulphur obtained from a single bore hole of a group of boreholes is often actually derived from fairly distant parts of the deposit. It is assumed here that the efficiency of sulphur exploitation highly depends on location of a borehole in relation to fracture systems.