to a question of determining the mining boundary angle in subsidence

The mining boundary angle, as one of the basic parameters of subsidence, is used a lot of methods at prediction calculation of movements and deformations. The mining boundary angle is used at determining so called the pillar angles at the protected pillar of warehouses on the earth surface. This mining boundary angle together with the mining depth characterises the subsidence measure on the earth surface. The mining boundary angle depends upon geological, hydrogeological relations and deformability of rock massif, upon excavation technology etc.The presented paper deals with determining the mining boundary angle on a base of geodetic measurements on the monitoring network points in the coalfield - OKR in the Czech Republic. The mining boundary angles of two monitoring stations: Stonava and Karvina-Solca are determined. The presented problem in determining the mining boundary angle and its authentication in the condition of OKR is summarised in the paper conclusions. There are alleged a few knowledge in the conclusions: shadiness in determining the mining boundary angle – uncertain limits of so called null influence, dependency of the mining boundary angle upon geomechanical properties and geological structure of the rock massif, the mining boundary angle depends upon geodetic measurement accuracy, etc.