A mounting assembly for supporting a fuel supply on a vehicle, which is specifically adapted for the operable support and positioning of an auxiliary fuel supply. The vehicle with which the mounting assembly is utilized may vary significantly, but is primarily structured for use on mine haul vehicles, bulldozers, and other heavy duty commercial vehicles, wherein the operation thereof is significantly benefited or enhanced through the provision of an auxiliary, or alternate fuel supply such as, but not limited to, liquid natural gas (LNG), selectively powering the engine of the vehicle as determined by an improved electronic control system. The mounting assembly comprises a containment structure in the form of at least one fuel tank and a housing is structured to enclose the fuel tank. A base supports both the housing and the fuel tank and a shield assembly, associated with the housing protect the fuel tank against impact in the working environment of the vehicle on which the fuel supply and containment structure are disposed.