For wireline core drilling. Rock cores can be retrieved without pulling out the whole drill string. A special wireline overshot passes through the central bore of drill rods to lift the core inner tube to the surface.

Standards
JIS G3465 Seamless steel tubes for drilling
GB/T 9808 Seamless steel tubes for drilling
GB/T 16950 Geological core drilling tools

Note: Grade A BL520 measures Rp0.5.
Grade B BL520 tensile specimens adopt S4, S5 or SG specified in GB/T 228.

Advantages

1. Reduces labor costs
2. Minimizes mechanical wear and wireline consumption
3. Improves borehole quality
4. Enhances core recovery rate
5. Saves auxiliary operation time
6. Flexible and durable auxiliary tools and equipment
7. High-strength inner and outer flat drill rods
8. Extends bit service life
9. Adopts optimized drilling and coring procedures