Experimental and Numerical Investigations on Rock Cuttability using Conical Picks Cutting: A Case Study in a Phosphate Mine

To investigate the rock cuttability in a phosphate mine in China, conventional rock mechanical tests and rock indentation tests were conducted on specimens sampled from five different rock layers. Rock strength parameters and maximum rock cutting forces were determined. Subsequently, numerical simulation was employed to further investigate the rock cuttability of the selected rock specimen through the rock linear cutting test. Unlike rock indentation tests, which determine only the maximum rock cutting force based on a single cutting cycle, numerical simulations can enable the determination of the maximum cutting force, average cutting force and specific energy (SE). The numerical simulation results for the maximum rock cutting force showed a good agreement with the experimental results after calibrating the numerical model and parameters. The results indicate that the rock strength of the Chuanyandong Phosphate Mine ranges from 21 MPa to 145 MPa. The maximum cutting force ranges from 0.85 kN to 2.88 kN, with an average value of 1.93 kN. The SE of ore body b is 10 kWh/m3. Additionally, the numerical simulation shows that the volume of rock cutting fragments increases linearly with the cutting displacement, and there is a significant influence of cutting velocity on the simulated rock cutting performance. Finally, the rock cuttability of the phosphate mine was classified based on rock strengths, cutting forces, SE and instantaneous cutting rate (ICR) predictions. In general, the rock cuttability improves with the decrease of rock strength, cutting force and SE, while the increase of ICR.