Link Latch™ Quick Pump-In™ Underground Head Assembly

The Link Latch™ Underground Head Assembly features dual lip seals and a pump-in valve for faster tripping times and positive latch indication; the location of the lip seals prevents in ground fluid or gas pressure from releasing the latches and eliminates the need for drive keys or tangs to keep the head spinning with the rods.

The head assembly also features the knuckle-head spearpoint for easier unloading of the inner tube in tight spaces, and the new retracting case allows loading of the head assembly into the rods without a loading sleeve.

Roller Latch™ Quick Pump-In™ Head Assembly

Patented Roller Latch technology on Quick Pump-In Head Assemblies offers an improved alternative to the conventional link latch mechanism. This technology allows for greater pump-in speeds and leads to increased productivity.

Roller Latch underground head assemblies utilize large ball bearings for reliable latching and holdback braking to retain inner tube assemblies in the drill string for safer operations. The head assemblies incorporate the MKII™ spearhead for added strength and safety. NQU and HQU Quick Pump-In Roller Latch underground head assemblies are equipped with variable lip pump-in seals that are compatible with V-Wall™ drill rods, offering the advantages of lightweight W-Wall rods in underground coring applications.


Quick Pump-In™ Overshot

Boart Longyear’s overshots are an integral part of the Q™ Wireline system. Once the inner-tube is full of core, the overshot is lowered (or pumped-in for an inclined-hole) to the bottom of the hole. Its heavy-duty lifting dogs grab a secure hold at the top of the inner-tube assembly.

For maximum productivity in underground or pump-in applications, the Quick Pump-In™ Overshot provides significantly improved pump-in rates with dual pump-in lip-seals; as well as new ‘V-Lip’ pump-in seals in NQ™ and HQ™ sizes. The variable profile of the ‘V-Lip’ seal provides improved performance and accommodates both standard wall and W-Wall™ drill rods when used with the new Roller Latch™ underground head assembly.

In addition, this overshot incorporates the proven Boart Longyear™ “Landing Indicator” ball and bushing. The ball and bushing provide a pump-in valve, a bypass valve, and a landing indicator pressure signal.


Roller Latch™ Underground Head Assembly


MKII™ spearhead assembly for added strength and safety features self-lubricating nylon to reduce wear, self-centering spearpoint with multiple detent positions, and an innovative design to eliminate pinch points.

Unique hold-back brake retains inner-tube assemblies in the drill string for safer operations in inclined and up-angle holes, as well as optional two-handed latch retraction for use without loading sleeves.

Roller Latches allow greater pump-in speed and productivity with diminished wear. The self-locking Roller Latch eliminates the need for adapter couplings and utilizes a newly-designed locking coupling.

Patented design with axial grooves and tapered profile is optimized for fluid flow and utilizes corrosion and wear-resistant components to ensure smooth and reliable functionality while offering less resistance in all hole angles

NQU™ and HQU™ Quick Pump-In™ Roller Latch head assemblies are equipped with new variable lip pump-in seals that are compatible with W-Wall drill rods, offering the advantages of W-Wall in underground applications.

Roller Latch head assemblies are safer and more reliable in underground applications, which allows drillers to maximize productivity.


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