A rippability classification system for marls in lignite mines

This paper describes the development of a rippability classification system for marls in lignites mines based on direct ripping runs, specific energy concept and indirect rippability assessment methods. Extensive field and laboratory studies were undertaken in six different panels of Turkish Coal Enterprises and Sivas-Kangal Lignite mines. Rock mass descriptions were made, seismic P-wave velocities are measured at the field, direct cutting tests and rock material property determination tests were carried out in the laboratory. The proposed method includes rock parameters such as uniaxial compressive strength, seismic P-wave velocity, discontinuity spacing and Schmidt hammer hardness value. In the developed method, rock properties are graded separately and rippability classes of rocks are determined according to the final grade. Appropriate dozer types and their productions are also proposed. Hence, both main components of rippability, rock and equipment properties are satisfied in the proposed system.