Performance prediction of roadheaders used in coal mines from the needle penetration index and the schmidt hammer value

Coal mine galleries and construction tunnels are commonly excavated using roadheaders. Estimating the performance of roadheaders is crucial for planning and cost estimation when planning tunnel or tunnel projects. The aim of this study is to derive generalized performance prediction models including Schmidt hammer value, needle penetration index, and volumetric joint count for roadheaders used in coal mines. The performance measurements of axial and transverse type roadheaders were carried out in six different coal mines. Schmidt hammer tests, needle penetration index tests, and of volumetric joint count measurements were also performed at the locations where the performance measurements were conducted. The extensive data were evaluated using multiple linear and nonlinear regression analysis. The developed formulas were evaluated using statistical tests. The Equations that include the Schmidt hammer value or needle penetration index value in addition to cutter head power have been shown to be unreliable. However, the equations that include Schmidt hammer value or needle penetration index value in addition to cutterhead power and volumetric joint count have been shown to be reliable. This study concludes that the developed reliable equations can be used for the performance assessment of roadheaders used in coal mines.