There are several types of mine cars that can be chosen for underground mining operations based on various factors. Granby cars are robust and suitable for high volume extraction of non-sticky ores. They dump to the side with a dolly wheel on a ramp. Rocker dump cars have a smaller 1-10 cubic yard capacity and can dump on either side, making them suitable for low capacity needs and sticky ores. End dump cars unload from the back and are used for hand tramming in small mines. Gable-bottom cars can be built for large capacities and variable gauges, allowing two-way dumping. Solid or box cars have high capacity but are less maneuverable and require rotary dumping. Choice factors include capacity, cost