Mesutoğlu, M.Özkan, İ.2021-12-132021-12-1320209780367422844https://hdl.handle.net/20.500.13091/99614th International Congress on Rock Mechanics and Rock Engineering, ISRM 2019 -- 13 September 2019 through 18 September 2019 -- -- 238139Schmidt hammer (SH) is widely used to predict uniaxial compressive strength (UCS) and other mechanical properties of rocks from surface rebound hardness values. The method has been extensively applied to the intact rocks so far and for this reason, the researchers have developed some methods for use in rock cores and blocks. At the same time, there is not enough information about the in-situ application of the Schmidt hammer. In this study, SHs were carried out in Tunçbilek-Ömerler underground coal mine. For this reason, four measurement areas were prepared on the longwall face. The measurement areas were firstly divided into a grid system, with each grid section having an area of 0.214 m2. At the end of the study, two hundred and fifty-five records were constructed using the data obtained from 4 longwall face positions, and also these were used for statistical analyses. The obtained results were compared with the approaches suggested by ISRM (2007), ASTM (2005) and Young & Fowell (1978). © 2020 ISRM.eninfo:eu-repo/semantics/closedAccessConference Object2-s2.0-85084679766