ABSTRACT: In mining projects, intact rock properties which are necessary for rock mass behavior can be determined by triaxial compression strength tests. Soma is one of the important coal basin where is 90km away from Manisa city in Turkey. In this basin, there are lots of open pits and underground coal mines. The marl formation of this area is the hangingwall of the main coal seam. This study is based on the concept of the intact rock properties' being representative for the marl rock mass. Soma marl includes calcite filled joints which are in different directions and 1–5mm thickness. In this study, while these joints are not being as weakness planes, rather than considering these joints as discontinuities, it is suggested to take them into account in intact rock structure. As a conclusion, following intact rock properties were proposed for Soma region marl: as 86.82MPa for the uniaxial compression strength, as 11.01 for the Hoek-Brown material constant, as 17.13MPa for the cohesion and as 43.99° for the internal friction angle.
1 INTRODUCTION Soma is one of the important coal basinwhere is 90 km away from Manisa city in Turkey, operated by Turkish Coal Enterprises (TKI). In this basin there are lots of open pits and underground coal mines. In mining projects, intact rock properties which are necessary for rock mass behavior can be determined by triaxial compression strength tests. Mohr-Coulomb and Hoek-Brown failure criterions have common usage in mining designs. From triaxial compression strength test results while intact rock cohesion (c) and internal friction angle (φ) would be obtained according to the Mohr-Coulomb failure criterion (Lambe and Withman, 1979), intact rock uniaxial compression strength (σci) and Hoek-Brown material constant (mi) would be obtained according to the Hoek-Brown failure criterion (Hoek and Brown, 1997).