Oahe mole

The "Oahe mole" refers to a pioneering tunneling machine developed for the Oahe Dam project on the Missouri River in South Dakota, which began in 1954. This machine, also known as the "Mittry Mole," was instrumental in the first successful machine-mined tunnels, achieving significantly faster excavation rates than previous methods.1

The development of the Oahe mole was inspired by earlier rotary excavators and was a collaborative effort involving engineers and contractors. This innovation paved the way for modern tunnel boring machines (TBMs), which have since become widely adopted for constructing tunnels worldwide, dramatically increasing tunneling speeds. The Oahe Dam project itself created Lake Oahe, a reservoir approximately 225 miles long.123