Publication details
Study of geomechanical conditions of magmatic rocks based on drillcore exploration of Cínovec deposit (Bohemian Massif)
| Authors | |
|---|---|
| Year of publication | 2019 |
| Type | Conference abstract |
| Citation | |
| Description | Drill exploration has been ongoing since 2012 in the Cínovec deposit. The core-drilling program has completed more than 30 core boreholes with an average depth of 300–400 m. Relative rock strength of selected drillcores was measured by the Schmidt hammer due to good experience from the previous research (e.g., Knížek et al. 2018). Discontinuities, structural deformations and other alterations were described at the same time. The Schmidt hammer is mainly used for civil engineering purposes (especially for strength measurement in concrete studies), but it can be also used for geological research. The equipment enables indirect detection of compressive strength by measuring scleroscopic strength (e.g., Aydin – Basu 2005). The ADA 225 device, equivalent to the Schmidt Hammer type N with a kinetic energy of 2,207 J, was used for the tests. This device can measure rock strength above 10 MPa. As the device is not used in a standardized manner and outside of the laboratory, the resulting values are not quantitatively accurate. The rock strength was growing under the eluvium. The changes of rock strength are reflection of local alterations of rocks and healthy or decomposed rocks. Disability of rocks (tectonic crushing, kaolinization and other alterations, chemical erosions) reduces strength. The research continues. Correlation of individual joints from the drill cores with the same joint systems from the rock outcrops was possible due to the statistical results of the altitude-dependent inclinations. The joint systems were oriented in two main directions NE–SW and NW–SE, which represent the systems of perforated structures to the Ohře rift. The joints with a subvertical inclinations are significant in the system with main direction NE–SW and the sloping joints are oriented in the second main direction SW–SE. This analysis can answer questions about geomechanical properties of rocks. The results of this study will be used for possible mining work etc. This approach can also be applied to other localities and it is also useful for other research of applied geology. |