TT Series Double Tube Core Barrels

TT core barrels are conventional double tube core barrels with an ultra-thin wall. They are designed for coring in medium hard to very hard homogenous rock in conjunction with water flushing. These core barrels are most frequently used for underground mining operations.

Available in metric (millimetre) hole sizes 46 and 56 mm


  • A high rate of penetration due to small cutting area of the core bit
  • Use of lower pressure and torque minimizes the wear on equipment
  • Lower costs for core bits
Technical Data
SpecificationCore Barrel Type
Hole Diameter (mm)46.356.3
Core Diameter (mm)35.345.2
Kerf / Crown Thickness (mm)5.355.4
Cutting Area (cm2)7.08.9
Hole Area (cm2)16.824.9
Cutting Area as % of Hole Area41.7%35.7%
Core Area (cm2)9.816.0
Thread Connection in Head*CR42CR50
Recommended CasingM56M66
Conversion to triple tube possibleNoNo

*Cross-over sub required for drill rods not matching the thread connection in core barrel head

Key to Main Parts of TT Core Barrel Assembly

Complete core barrel consists of:

1. Core Barrel Head

2.  Inner Tube 1.5m or 3.0m

3. Outer Tube 1.5m or 3.0m

4. Extension Tube

5. Core Lifter

6. Core lifter Case

Core Bit and Reaming Shell are not supplied as part of the core barrel assembly, but must be chosen correctly to match the particular application and rock formation. Please refer to our Core Bits page for further details.