An astro-miner was a mobile shipyard built by the U'lanna, building starships out of asteroids. The Stoneship (BC-347) encountered a rogue astro-miner in the Idlewild system, building a Khin'Vagh-class dreadnought out of asteroids. It was destroyed by ramming a K'pak-class corvette. (Star Trek: The Stoneship Files: "A Knight without Armor")