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• An indirect measurement model for coal and rock interface identification is proposed by quantitative analysis of rock proportions in cutting range. • The model is still applicable even if in conditions where rock material properties are unknown in advance. • The method is also applicable for interface identification of two kinds of material in other rotary cutting machine in addition to shearer drum in the paper. In coal mining industry, direct measurement on rock proportions is difficult due to various rock material properties. Aiming at identification of coal and rock interface, the paper proposed a method by indirect measurement on rock proportions with contact force and some measures to improve the measurement accuracy as well. To establish the measurement model, cutting forces under different kinds of working states are studied with theoretical analysis and the relations between rock proportions and dynamic force are established. For validation, general circumstances with various rock properties and motion parameters in mining process are studied and estimation results of rock proportions in those circumstances are analyzed. Results show that the measurement accuracy is stable even if parameters related with rock properties and drum working parameters are different. Therefore, the mentioned parameters are no longer essential in advance for indirect measurement of rock proportion. In addition, stochastic fragmentation of coal or rock always leads to fluctuation on measurement accuracy. With the improved cluster method, the mean accuracy of this model are close to 90% and sometimes, the measurement accuracy is even more than 95%. The method in this paper is meaningful for identification of coal and rock interface and in this way could guide the shearer drum to avoid hard rock to reduce the damage on mining equipment. [ABSTRACT FROM AUTHOR]

• Hard rock cutting hastens heat accumulation on pick body and metal softening; • Wear of cutter in hard rock cutting with and without coolant conditions is analyzed; • Thermal effect is taken into consideration during measurement of rock abrasiveness. Conical picks are widely used in fields such as tunnel excavation, and high temperatures often occur on the surfaces of conical picks during the hard rock cutting process. To explore the influence of temperature on the wear of conical picks, a rotary cutting test was arranged. The cutting head torque, heat distribution and wear on the conical pick at different rotating speeds and cutting depths were explored. Moreover, the working process with and without cooling liquid was taken into consideration, and the mass losses of the conical pick under those conditions were analyzed. The experimental results showed that under cooling liquid conditions, the maximum temperature on the conical pick decreased by 230°C, and the mean mass loss of the conical pick decreased by 15.8 g. Therefore, high temperature could not be ignored in hard rock cutting. On the basis of these findings, a method for the measurement of rock abrasiveness was proposed in this paper, and different from previous research, the thermal effect was taken into consideration. A test bed for rock abrasiveness measurement was assembled in which a sintered WC-Co rod was used for rotary grinding on the rock sample, and the mass loss of the grinding rod was determined to evaluate the rock abrasiveness. The loading force between the grinding rod and rock sample was considered in the measurement of rock abrasiveness. The results showed that the mass losses of sintered WC-Co rods increased with the loading force. In addition, the characteristics of oxygen found from scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) showed that peeling and cracking could be found at distances of 5 mm and 10 mm from the end face of the grinding rod, and the increased oxygen content suggested obvious oxidization at those regions as well. [ABSTRACT FROM AUTHOR]