Stope stability analysis of limestone ex-mined area at Ponjong sub-district Special Region of Yogyakarta using finite element method

Abstract

Limestone mining activity in Gunungsewu karst terrain of Gunung Kidul, Yogyakarta has been long time to be the livelihood for local communities. Evidently, by the number of ex-mining that have not been maintained and one of them looks like a stope hole in underground mining and failures could be occur at the stope. In this case, the sustainability of geoheritage area required geothecnical analysis to anticipate possibility of failure. This research conducted on traditional mining area in Sidorejo Village, Ponjong sub-district, Gunungkidul by comparing between the Hoek Brown and Mohr Coulomb failure criterion. Hoek-Brown criterion considering the geologic structures of rock mass and classification of rock mass using Geological Strength Index (GSI) whereas Mohr-Coulomb criterion is based on laboratory testing of intact rocks that will be affect to the value estimation of sigma 1, sigma 3, strength factor, and total displacement at the stope. Stability of stope will be analysed using finite element method that assisted with software Phase 2. The result of this research can be used as a reference to determine an appropriate acts to preserve the Gunungsewu geoheritage area.