Diesel power units operated in underground coal mines are designed to comply with regulatory guidelines specifying the management of pollutants in underground environments. This promotes the safety of explosion protected power systems that are used in underground coal mines, ensures key safety measures are followed and minimises the risk to the health and safety of mine personnel. Diesel engines provide a reliable, simple and efficient form of power generation, though emphasis is now on clean and safe forms of power generation. Mine operating conditions are becoming more complex with increasing constraints, influencing how future resource extraction will need to be accomplished. The reduction of power unit emissions beyond current mandated levels, particularly Diesel Particulate Matter (DPM), will face significant technical and operational challenges due to the unique environment in underground coal mines. In addition to improved capital efficiency, future mining will require reductions in energy use. The reduction of emissions from power units complying with changing government policy contexts on emission output within mining operations will assist the aim to increase energy efficiency. The project objective was to provide an overview of the requirements of control of emissions in underground coal mines and the technological challenges involved in further reducing emissions to achieve stringent compliance levels, through the introduction of advanced power unit technology. To achieve reductions in emissions, Original Equipment Manufacturers (OEM) must improve machine design, efficiency and component selection. Different power unit alternatives were assessed in this project and compared to the current Diesel Engine System (DES) used in Sandvik flameproof Load Haul Dump (LHD) machines, which has been used as a benchmark for the comparison. The project analysis concluded that a diesel electric hybrid power unit with a Tier 2 engine, Oxidation Catalyst (OC) and Diesel Particulate Filter (DPF) is the most suited as a power unit alternative in comparison to the benchmark power unit. A diesel electric hybrid power unit improves on key criteria effecting the change from the current benchmark power unit, to one aiming to be more efficient, to reduce emissions and maintain or exceed current industry standards of operation and reliability