Back Reamer

A cutting head attached to the leading end of a drill string to enlarge the pilot bore during a pull-back operation to enable the carrier or sleeve or casing to be installed in.

Backfall

Refers to a length of pipe having an upward gradient opposite to the direction of flow.

Backfill Density

Percent compaction for pipe backfill (required or expected).

Backflow Device

Mechanism that prevents wastewater from flowing back upstream.

Backstop

Reinforced area of the entrance pit wall directly behind the track.