Core Drill

Barrel drills are divided into two main categories: core-retaining annular barrel drills and non-core-retaining annular barrel drills;
Suitable for relatively hard bedrock formations, large boulder layers, and hard permafrost layers, where direct drilling with auger drills or rotary drilling bits is difficult,
drilling requires the use of annular barrel drills in combination with auger drills and sand bailer drills.