The Database tracks the largest mining dozers in operation at surface mines around the world. The current active mining dozer population for units with net power ratings of 350kW (500 hp) and above is 16,400 machines with 21,300 in total, counting those that are inactive or decommissioned. These are grouped into the size classes listed below. The primary manufacturers of the largest mining tractors are Caterpillar, Komatsu and Liebherr