Advance

1. The work of excavating as mining goes forward in an entry and in driving rooms; to extract all or part of an area; first mining as distinguished from retreat. BCI
2. Rate at which a drill bit penetrates a rock formation. Long
3. Feet drilled in any specific unit of time. Long
4. The linear distance (in feet or meters) driven during a certain time in tunneling, drifting, or in raising or sinking a shaft. Fraenkel
   Source: Dictionary of Mining, Mineral, and Related Terms