Groundhog's development began in the Fall of 2002 by the CMU Mine Mapping Team [10,24]. The robot was extensively tested in a well-maintained inactive coal mine accessible to people: the Bruceton Research Mine located near Pittsburgh, PA. However, this mine is technically not abandoned and therefore not subject to collapse and deterioration. On May 30, 2003 Groundhog finally entered an inaccessible abandoned mine in fully autonomous mode. The mine is known as the Mathies mine and is located in the same geographic area as the other mines. The core of this surface-accessible mine consists of two 1.5-kilometer long corridors which branches into numerous side corridors, and which are accessible at both ends. This was an important feature of this mine, as it provided natural ventilation and thereby reduced the chances of encountering combustible gases inside the mine.
To acquire an accurate 3D map of one of the main corridors, the robot was programmed to autonomously navigate through the corridor. 250 meters into the mine, the robot encountered a broken ceiling bar draping diagonally across its path. The robot made the correct decision to retract. The data acquired on these runs has provided us with models of unprecedented detail and accuracy, of subterranean spaces that may forever remain off limits for people.