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Abstract

The subject of the research was the Middle Miocene red algal limestone from the Włochy deposit, which is currently the only place of exploitation of the Pińczów Limestone representing a local type of the Leitha Limestone. The collected samples of this rock belong to the organodetric facies of diverse grain size and sorting of clastic material. Considering the proportions of characteristic skeleton remains, the composition of the coarse-grained organodetric facies is red algal-foraminiferalbryozoic, while of the fine-grained facies is foraminiferal-red algal. The cement of these rocks is predominantly sparite compared to micrite-clay matrix. A complement to petrographic studies was the chemical analysis and identification of mineral phases with X-ray diffraction. Moreover, physical and mechanical properties of samples were analyzed. Porosity of the rock was assessed in the polarizing and scanning microscope (SEM-EDS) observations, as well as with a porosimetric tests. The coarse-detrital limestone with a dominant binder in the form of intergranular cement is characterized by the apparent density sometimes exceeded 1.90 Mg/m3, while fine-grained limestone has the highest water absorbability (above 20%) and total porosity (about 40%). The above properties influenced high water absorption by capillarity, limiting the possibility of using limestone in places exposed to moisture. The observed relationship between the ultrasonic waves velocity and the uniaxial compressive strength gives the possibility of predicting the value of the latter parameter in the future. The limestones from Włochy deposit do not differ in quality from the previously used Pińczów Limestones, and their technical parameters predestine them for use as cladding material with insulating properties.
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Abstract

A lithological profile and measurements of the orientation and spacings of natural discontinuity planes were carried out in the Górka-Mucharz sandstone excavation (Krosno Beds, Outer Carpathians, Poland). In addition, the density of the discontinuities was assessed by measuring their spacings using oriented digital photographs of the quarry walls. An orthophotomap was also used in assessing the orientation and density of fractures with the tools available in QGIS. It was shown that digital image analysis can be used as an alternative to direct field measurements, especially in situations where access to an outcrop is difficult. The distributions of spacings larger than 40 cm, obtained by direct measurements and based on digital images of the quarry, were comparable. As a consequence, both measurement techniques yielded similar values of the quantity of blocks (QB), which differed by less than 2% for the minimum block volume in the range 0.4-1.0 m3 and by 6-7% for larger blocks. On the other hand, measurements of discontinuity spacings that were taken on the basis of an orthophotomap can only serve to estimate the approximate maximum value of this parameter. However, the use of orthophotomaps gives a more explicit spatial pattern of the main vertical joint sets than direct measurements in the quarry. The analysis results also showed the following: (i) the presence of tectonic disturbances visible at the highest level of the deposit; (ii) higher density of set A fractures with planes deepening in the NE direction and a considerable reduction of the QB parameter, particularly in the peripheral NE and SW parts of the deposit; (iii) differences in the orientation of the discontinuity system between particular beds. The variable density of the discontinuities in the excavation is related to the presence of the faults that limit the Górka-Mucharz deposit.
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