Experimental validation of the predicted peak cutting force for seafloor polymetallic sulfide

Abstract With the gradual reduction of mineral resources, marine mining has increasingly been developed as a method of exploiting resources. However, the cutting efficiency of submarine mineral deposits requires additional improvement. Investigating the preferable cutting efficiency in marine mining, it is important to establish a theoretical model of predicting the peak cutting force for polymetallic sulfide. The polymetallic sulfide was taken from the floor of the Indian Ocean and maintained at constant temperature and humidity conditions during transportation. In the paper, some experiments were conducted to study the physicomechanical properties of polymetallic sulfide. And the cutting experiments were conducted to investigate the cutting force at room temperature and atmosphere pressure, preliminarily. Then, based on maximum tensile stress theory, the theoretical equation of predicting the peak cutting force was derived, and an improved high-precision theoretical model was established. The reliability and accuracy of this model was verified using the experimental data. Based on the improved theoretical model, the brittleness index and the cutting depth, which influenced the peak cutting force, were investigated. Results show that the established model improved the accuracy of predictions. The peak cutting force decreased with the increase of the brittleness index, but it increased with the increase of the depth, which followed the power-law pattern. The power-law coefficient was generally at 1-2. The experiments verified that this improved theoretical model and the related conclusions can predict the peak cutting force. It is significant for the design and study of conical picks and cutting mechanisms in marine mining.