The increased use of diesel engines in underground mines, together with increased mine depth, cause challenges in maintaining diesel particulate matter (DPM) at acceptable levels in underground environments. In 2012, the International Agency for Research on Cancer (IARC) classified DPM as carcinogenic to humans. To control the DPM exposure, it is important to understand DPM distribution and dispersion characteristics. In this study, an isolated zone in an underground mine in the US was taken as the physical model and the computational fluid dynamics (CFD) method was used to study the DPM distribution for two operational scenarios. The simulation results were compared with existing validation data. Compared to studies that treat DPM as a continuous phase, a better agreement with the experimental data is achieved in this study which uses the discrete phase to represent DPM. High DPM concentrations were identified in the two scenarios. This information can be potentially used to optimise auxiliary ventilation designs. (C) 2018 Elsevier B.V. All rights reserved.