big-hole drilling

excavation

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Last updated

June 22, 2026

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Big-hole drilling is a specialized excavation technique used to create large-diameter holes, typically in rock. This method is an adaptation of oil-well-drilling techniques and is primarily employed for deep emplacements, such as in underground nuclear testing.1

The process involves using an array of roller-bit cutters that are pressed against the rock by the weight of heavy, lead-filled drill collars. The drill rig itself must be substantial to manage these loads. A key challenge in big-hole drilling is the efficient removal of drill cuttings, with airlifts showing promise for this purpose. This method has been used to drill holes up to 5,000 feet deep.1

While "big hole" can also refer to the emergency application of brakes in railroading, in the context of excavation, it specifically denotes this large-diameter drilling method.2

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tunnels and underground excavations
Shaft sinking and drilling
…methods in a technique called big-hole drilling, used for constructing small shafts in the diameter range of three to six feet. Big-hole drilling was developed for deep emplacement in underground testing of nuclear devices, with more than 150 such big holes drilled in the 1960s up to 5,000 feet deep…
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…methods in a technique called big-hole drilling, used for constructing small shafts in the diameter range of three to six feet. Big-hole drilling was developed for deep emplacement in underground testing of nuclear devices, with more than 150 such big holes drilled in the 1960s up to 5,000 feet deep…
Read More