In slurry shield tunnel boring processes, the cutter head is filled with pressurized slurry (a suspension of bentonite or a clay and water mix) that lubricates and applies hydrostatic pressure to the excavation face. On the return line, the slurry acts as a transport medium that carries the debris/soil to a slurry separation plant outside the tunnel. Accurate density measurement in the lower density supply line as well as in the high solids return line are good indicators of tunneling productivity. The ADM is a robust and easy to use solution for density measurement, it can be used underground, and its wide density measurement range and fast response time makes it suitable for both TBM applications.