  In the near future the energy region above few hundreds of TeV may really be
accessible for measurements of the atmospheric muon spectrum by the IceCube
array. Therefore one expects that muon flux uncertainties above 50 TeV, related
to a poor knowledge of charm production cross sections and insufficiently
examined primary spectra and composition, will be diminished. We give
predictions for the very high-energy muon spectrum at sea level, obtained with
the three hadronic interaction models, taking into account also the muon
contribution due to decays of the charmed hadrons.
