  The Monte Carlo program ARROW, based on GEANT and using GHEISHA at energies
below 30 GeV, is developed for simulation of the hadron and muon components of
extensive air showers with primary energy $10^{12}-10^{17}$ eV. Calculations of
the characteristics of multi-muon events as observed underground by the LEP
detectors are presented and their dependence on the primary cosmic ray
composition and some basic assumptions of the hadronic interaction model is
discussed.
