Cosmic neutrinos are expected to include a significant flux of tau neutrinos due to flavor mixing over astronomical length scales. However, the tau-neutrino content of astrophysical neutrinos is poorly constrained and a significant flux of cosmogenic tau neutrinos awaits discovery. Earth-skimming tau neutrinos undergo charged-current interactions that result in a tau lepton exiting the Earth. The tau lepton decay generates an extensive air shower and geomagnetic radio emission. To target the tau neutrinos, I will present a new tau neutrino detector concept that uses phased antenna arrays placed on high elevation mountains. Simulation studies indicate that a modest array size and small number of stations can achieve competitive sensitivity, provided the receivers are at high enough elevation.