Mining ships are used to remove valuable ores, minerals, metals and other resources from asteroids and planets (hull size 8-20). The ship's processing facilities remove valuable materials from the rock or dirt being mined and jettison the tailings. When a planet is mined, the mining ship sends several shuttles (carried in the miner's cargo hold) down to the surface, where the digging and processing takes place. Only the valuable materials are brought back to the ship. The processed materials are loaded into the shuttle hangars and the shuttles are left behind when the miner returns to its base. When an asteroid is mined, the processing takes place in the mining ship. Digger shuttles are used to bore into the asteroid and carry the raw ore back to the mining ship.
Although many planets consist of nothing but worthless rock and low grade iron ore, others are fairly bursting with valuable metals, gems and other resources. Determining whether a planet has natural resources worth mining involves as much luck as science - often a lot of prospecting and following rumors. Because of the potential for fat, fast profits, mining operations are plump targets for pirates and unethical corporations.
Some of the more heavily populated resource-rich worlds in the Frontier have been mined to the point where the planet becomes an industrial wasteland. The lessons learned from these experiences have led some planetary governments to pass tough environmental protection laws. Such laws can be a major obstacle for an ambitious mining operation.