What is the method for removing sand that has entered the hollow-stem auger after you have drilled below the water table?

• A. Remove using a shovel
• B. Wash the sand out with approved water
• C. Use compressed air to blow out
• D. Let it drain and pull out

Answer: (B)

When sand has entered the hollow-stem auger after drilling below the water table, the best way to clear it is to wash the sand out with approved water. The hollow stem serves as a conduit for fines, and a controlled water flush suspends the sand and carries it up and out through the surface return or discharge line. This creates a clean, continuous pathway for continued drilling and helps prevent packing or binding inside the stem.

Shoveling isn’t effective because it can only move surface material and risks reintroducing sediment or damaging the equipment. Using compressed air can push or pack the sand deeper or create dangerous blowback and is not a controlled method for clearing fines. Simply letting the system drain and pulling out leaves the sand behind, which can cause blockages or erosion of the borehole.

Using approved water ensures a safe, controlled removal of the sand while maintaining borehole stability and preventing contamination. Make sure the water source is approved, and apply a steady, appropriate flow to flush the sand all the way out to the surface.