  An ultra-large Liquid Argon Time Projection Chamber-based neutrino detector
will have the uncommon ability to detect atmospheric tau neutrino events. This
paper discusses the most promising modes for identifying charged current tau
neutrino interactions, and shows that, with simple kinematic cuts, ~30 tau
neutrinos can be isolated in a 100 kt*yr exposure, with greater than 4 sigma
significance. This sample is sufficient to perform flux-averaged total
cross-section and cross-section shape parameterization measurements -- the
first steps toward using tau neutrinos to search for physics beyond the
Standard Model.
