mole

tunneling machine

Also known as: rotary excavator, tunnel-boring machine, tunneling mole(Show More)

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Last updated

June 30, 2026

Quick Summary

A mole, or tunneling machine, is a specialized piece of equipment used for excavating tunnels. Since their introduction in 1954, moles have been widely adopted for both soft-ground and hard-rock tunneling.12

These machines typically excavate by using drag teeth or cutters and discharge the removed material onto a conveyor belt. Many moles operate within a protective shield. Different types of moles exist, including open-face-wheel, closed-faced-wheel, and pressure-on-face designs, each suited for various ground conditions. Rock moles, in particular, create a smooth tunnel surface, minimizing damage to the rock and reducing the need for extensive support structures. Moles can achieve high advance rates, often surpassing traditional drilling and blasting methods, and are increasingly being developed to handle more complex tunneling tasks.123

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