Overshot&Accessories

The overshot assembly is a core equipment used in geological drilling and mineral exploration for efficiently obtaining rock cores. Its core function is to quickly retrieve the inner tube containing the rock core through the steel wire rope without removing the drill pipe. This technology significantly improves the core-sampling efficiency, reduces the time for drilling up and down, and is widely applied in the exploration of complex formations.

Working principle

Drop the salvage device

Lower the salvage device assembly to the bottom of the hole through the steel wire rope, close to the top of the inner tube of the core.

Lock the inner tube

After the salvage spear comes into contact with the salvage neck of the inner tube, the retaining rings expand and clamp the inner tube under the action of spring force or hydraulic pressure.

Enhance recycling

Tighten the steel wire rope, lift the inner pipe and core to the ground, and there is no need to lift the drill pipe throughout the process.

Separate the core

Remove the inner tube from the ground, take out the core, and then re-insert the inner tube to the bottom of the hole to continue drilling.

Technical advantage

High efficiency: The single core sampling time is shortened by more than 50%, reducing the energy consumption of the drilling rig idling.

High core quality: Avoid core detachment or disturbance caused by frequent drilling.

Safety: The tripping device prevents the steel wire rope from breaking due to overload.

Economy: Reduces drill pipe wear and labor costs, especially suitable for deep holes (>1000 meters).

Adaptability: It can operate stably under complex conditions such as inclined holes and fractured strata.