ORIGINAL PAPER Study of correlation between specific energy of cutting and physical properties of rock and prediction of excavation rate for lignite mines in C ¸ ayırhan area, Turkey Cihan Dogruoz 1 • Jamal Rostami 2 • Serhat Keles 3 Received: 4 August 2016 / Accepted: 7 July 2017 Ó Springer-Verlag GmbH Germany 2017 Abstract Laboratory specific energy (SE) is a reliable indicator to evaluate the rock cuttability and efficiency for mechanical excavation in mining and tunneling applica- tions. In this study, various geological units encountered in lignite mines were studied through laboratory tests and measurement of specific energies in nine different rock types and two different lignite samples from C ¸ ayırhan area, Ankara, Turkey. The correlation between the physical and mechanical properties of various rock including uniaxial compressive strength, tensile strength, cone indenter hardness, shore hardness, Schmidt hammer hardness, and density with measured SE of cutting were also investigated. A prediction model for SE based on statistical analyses using regression technique of laboratory test results are also introduced. The model can be used for estimating the SE from the rock physical and mechanical properties, and in turn offer an estimate of machine performance for per- tinent mechanical excavators such as roadheaders, contin- uous miners, and drum shearers. Keywords Laboratory specific energy Á Cayirhan lignite Á Instantaneous cutting rate Introduction Performance of mechanical excavators depend on a variety of factors, including mechanical properties of the rocks and rock mass conditions (Dogruoz et al. 2016). Many studies have been conducted to investigate rela- tionships between the specific energies of cutting and rock properties (Fowell 1973; McFeat-Smith and Fowell 1976, 1977; Gehring 1989; Neil et al. 1994; Bilgin et al. 1996; Thuro and Plinninger 1999; Goktan and Gunes 2005). McFeat-Smith and Fowell improved an existing standard cutting test and observed a close relationship between specific energy (SE) and the production rate of roadheaders in the field (Fowell and Pycroft 1980; Fowell and Johnson 1982). Similar relationships have also been found by other researchers for roadheaders of different sizes (Balci and Bilgin 2005). The focus of this paper is to examine the relationship between specific energy (SE), instantaneous cutting rate (ICR), and various rock properties of rock strata in C ¸ ayırhan colliery. This relationship was subsequently used to develop some models for estimation of SE from commonly available rock properties and use it to esti- mate the cutting rate of the pertinent partial face mechanical rock excavation machines. The research sig- nificance of this study is to analyse the correlation between the instantaneous cutting rate taken from C ¸ ayırhan area and the specific energies calculated in laboratory conditions. Moreover, rock mechanic param- eters and the results of statistical analysis show strong relationship between these tests. The formula to predict the instantaneous cutting rate is applicable to the rocks and C ¸ ayırhan lignites with minimal amount of disconti- nuities or joints. & Cihan Dogruoz cihan.dogruoz@dpu.edu.tr 1 Department of Mining Engineering, Dumlupinar University, Kutahya, Turkey 2 Department of Mining Engineering, Colorado School of Mines, Golden, CO, USA 3 Department of Mining and Minerals Engineering, Virginia Polytechnic Institute and State University, Blacksburg, USA 123 Bull Eng Geol Environ DOI 10.1007/s10064-017-1124-2