A probabilistic approach for assessing failure risk of cutting tools in underground excavation

Accurate assessment of failure risk of cutting tools is essential to the optimization of cutter and drum design as well as the operation of mechanical excavators. In reality, factors involved in the risk assessment often have many uncertainties, e.g., the variations in rock properties and cutting tip material properties. In current practice, these uncertainties have not been considered adequately. The conventional deterministic approach based on mean values or extreme values normally generates a binary assessment (safe or unsafe) and can lead to over- or under-estimation of cutting tool failure risks. To address this issue, a probabilistic risk assessment approach is proposed in this paper, with a case study on the application of the proposed approach to the failure probability assessment of cutting tools for underground roadway development with a continuous miner. In this approach, the property variations of cutting tools and rock are modelled using probability theory, the continuous rock cutting process is discretized, and the failure risk of cutting tools is estimated based on reliability theory. The new approach enables designers and operators to estimate how likely a cutting tool would fail in a given operational condition, and then adjust their design and operation decisions accordingly to achieve an optimal balance between cutting productivity and cutting tool failure risk.