The Drill Mod 1 is an augment that can be used to drill through harder terrain than the unaugmented Terrain Tool allows.
To use the Drill Mod 1 it needs to be attached to one of the three slots on the Terrain Tool. Use the tool as normal to dig through soil. Use of the drill mod requires power, and it will drain the backpack supply quickly. For longer use connect to tethers or have power generating items in the backpack, such as a Small Wind Turbine or Small Generator.
It is best to use the drill mod on soil that the terrain tool struggles to or cannot dig through.